Water: The Epic Struggle for Wealth, Power, and Civilization - Steven Solomon (2010)

Part I. Water in Ancient History

Chapter 4. Seafaring, Trade, and the Making of the Mediterranean World

On the dry, hilly, island-flecked eastern Mediterranean fringes of antiquity’s irrigated empires arose a cluster of seafaring societies that secured their wealth and defense primarily through maritime commerce and naval power. Over time these small states spawned a different kind of civilization that contrasted starkly with that of the centralized, authoritarian hydraulic societies. Its distinctive characteristics were a private-sector market economy, individual property and legal rights, and a representative democracy for those who qualified as citizens. Taking form first in ancient Greece, its traditions spread through the Mediterranean world with the Hellenist diaspora, the reach of the Roman Empire, and later through the activities of the small seafaring republics Venice and Genoa. With the eventual breakthrough of global ocean sailing in the sixteenth century, it rose to world prominence through the influence of leading Western liberal market democracies, the Dutch United Provinces, the British Empire, and the United States. Today, its imprint informs many prevailing norms of the integrated global economy.

The small, ancient maritime trading states of the eastern Mediterranean were forced to international seafaring not by preferred choice, but because of their domestic agricultural and water resource limitations. Their scant rainfall, hilly terrains, small strips of arable land, and short rivers unsuitable both for long inland navigation and mass-irrigated farming simply were inadequate to produce enough food to sustain large, prosperous populations. Yet the challenges of their harsh geography did present one opportune route to increase economic surplus. The sea itself, for those able to master the art of navigating its waters, offered a ready and cheap highway to link societies along its length that were willing to exchange their grain and other basic resources for the specialized goods produced indigenously around the Aegean—above all, its prized olive oil and wine. The region’s jagged coastlines also presented good harbors conducive to maritime trade and fishing. The formidable natural sea barrier itself, furthermore, helped defend the independence of small states against the superior armies of the land-based hydraulic empires nearby.

For ancient Aegean civilizations, transport by sea came to play a role analogous to that of river transportation in Egypt and Mesopotamia. Despite its 2,500-mile length and stormy dangers, the tideless, shallow, and relatively tranquil Mediterranean (Greek for “sea between the land”) was one of Earth’s most welcoming seascapes for sailors. Save for the narrow eight-mile-wide passage at the Strait of Gibraltar—known in antiquity as the Pillars of Hercules—opening to the Atlantic Ocean, it was virtually an immense, enclosed lake. At its northeast extremity a pair of twin straits, the Dardanelles (known as the Hellespont in antiquity) and the Bosporus, separated Europe from Asia and led to the huge inland Black Sea and the resources of central Asia. In the southeast, between Egypt’s Nile delta and the Sinai Peninsula, only a small neck of land separated it from the Red Sea and beyond to the Indian Ocean. On its eastern rim the wealthy ports of the Levant offered access to goods arriving by overland caravans from all over the Near East and beyond. Within its civilized circumference arrived all the food, raw materials, manufactured goods, and luxuries necessary to support an accomplished maritime trading civilization.

In antiquity three main sea trade routes traversed the length of the Mediterranean: one sailed along the shoreline ports of southern Europe; a parallel southern route tracked the harbors of North Africa; the third, central route sailed the open waters between major islands such as Cyprus, Rhodes, Crete, Malta, Sicily, Sardinia, and the Balearics. Each could be navigated simply by following a series of visual landmarks without need of a compass or sextant. The gravest peril was frequent winter gales, which changed direction rapidly and created treacherous crosscurrents. Thus, for most of ancient history, the main sailing season was confined to April to October. Due to the unidirectional, west-to-east direction of the winds, easterly sailing toward Levantine entrepôts was speedy by the travel-time measures of the ancient world. Distances in the opposite direction, by contrast, seemed immense and required laborious and skillful effort of oar and sail—it commonly took up to sixty days to navigate from the Levant to the Mediterranean’s midway point, where the sea was nearly land-bridged by the large island of Sicily. Indeed, the Sicilian bar effectively created two Mediterranean basins, a western and an eastern, that developed as more-or-less self-contained worlds. In the western Mediterranean in the third and second millennia BC, a vanished, ancient seafaring people laid thousands of puzzling religious stone megaliths on the arc of islands and shorelines stretching from Malta, Sardinia, Spain, and Morocco, up the North Atlantic coast to Brittany, Ireland, and Stonehenge, and into the northern seas as far as Scandinavia. In the eastern Mediterranean basin an enduring, robust seafaring civilization developed that shaped the course of history.

Mediterranean World


Sea trade in the Mediterranean advanced during the fourth millennium BC with the development of large cargo vessels constructed of planks and powered by sails as well as traditional oars. By combining the force of the winds with the water’s properties of low friction and buoyancy, sails enabled cargoes to be shipped efficiently over long distances in an age when overland transport was slow, perilous, and often impossible. Thus was established the large cost advantages of sea transport over land that has endured to the present day, and with it an international marketplace that gave societies a chance to increase wealth through economic specialization, including those specialized in facilitating trade. A further advance came after 2200 BC when the rudder was introduced to supplement the steering oar.

The distinction of being history’s first true great Mediterranean maritime civilization belonged not to the precocious but timidly shore-hugging Egyptians, but instead to an island people born on the sea—the Minoans of Crete. It was the Minoans who blazed many of the early Mediterranean trade routes. By 2000 BC, Crete was the trade crossroads of the region and for over half a millennium exerted a powerful economic, cultural, and naval influence throughout the Aegean and the eastern Mediterranean. The slender, 160-mile-long island’s most important natural asset was its strategic location between the lucrative markets of the Levant, Asia Minor, and Egypt and the raw materials of the western Mediterranean. The Minoans were especially well positioned to profit from the Bronze Age because from Crete they could easily bring together both bronze’s constituent metals—copper from the traditional deposits of neighboring Cyprus and Cilicia on the southern Anatolian coast, and tin from the mines of Etruria (Italy), Spain, and overland from distant Gaul and Cornwall, England. Bronze had first appeared in Mesopotamia around 2800 BC, and in Egypt by 2000 BC. Minoan workshops added further wealth by producing outstanding metalwork, weapons, tools, and pottery that were desired throughout the Old World. Minoan sea power rested on two kinds of vessels—a commodious, rounded, slow-sailing merchantman for commerce and a sleek and nimble long ship for raiding and defense that cruised under a single sail until battle, when its lone bank of oarsmen maneuvered its pointed ram into its enemy’s hull.

As their wealth accumulated, the Minoans constructed lavish, multistoried palaces and large cities, and devoted themselves to the arts of civilization. One striking feature of their greatest city, Knossos, was that in an age of heavy fortification, it remained unwalled. This was one of history’s earliest testimonies to the major defensive advantage provided by the open sea throughout the age of sail, as well as to the supremacy of the Minoan navy. Their domestic waterworks were sophisticated. Water tanks at the palaces of King Minos—probably a title, like Pharaoh, that applied to every ruler—flushed away human waste from indoor lavatories, while its cities were underlain with terra-cotta drainpipes and sewers. Agriculturally, terraces and dams maximized Minoans’ potential to grow olives and grapevines on their island’s semiarid, mountainous terrain. As the Minoans settled the Aegean, they passed much of their civilization, including an early form of Greek writing, on to the ancient Greeks who followed them.

Minoan life was cataclysmically disrupted around 1470 BC by a huge volcano 70 miles to the north that vaporized most of the island of Thíra (Santorin). The explosion rocked Crete with earthquakes, clouds of ash that buried some of its cities, and a huge tidal wave that decimated the harbors along its northern coast. Greatly weakened, the Minoans survived only a century more before succumbing to a rising culture on mainland Greece that they had helped nurture, the Mycenaens.

Until about 1200 BC, the Greek-speaking Mycenaeans flourished on the trade routes and predatory naval power acquired from the Minoans. Mycenae itself was the city-state, according to Homer’s Iliad, ruled by King Agamemnon, who led the Greek city-states in their concerted naval and armed forces campaign from about 1184 BC against the walled fortress city of Troy to retrieve the beautiful wife of his brother, King Menelaus of Sparta. But it wasn’t Helen’s face alone that launched the Greeks’ celebrated thousand ships. It was the lure of booty. Perched on a hill in northwest Asia Minor overlooking the mouth of the Hellespont, Troy possessed great wealth from tolls on passage through that strategic strait, its silver mines, and payment of tribute from its weaker neighbors. Nor was it the artifice of the wooden Trojan Horse that was chiefly responsible for Troy’s ultimate defeat. It was the Mycenaeans’ incomparable fleet, which gave them uncontested control of the sea supply lines and the ability to sustain the ten-year-long siege that ended with the sack of Troy.

Yet even by the time of the Trojan War, Bronze Age Mycenaeans and other Aegean mainlanders were being displaced from their homes by invaders from the north armed with superior iron weapons. Many took to the seas and became the Sea Peoples who raided Egypt at the end of the New Kingdom. Many Mycenaean refugees ultimately resettled on the Aegean Islands and the rugged Ionian coast of Asia Minor and endured the dark age that disrupted civilized life throughout the Mediterranean and the Near East for three centuries.

When advanced civilization reemerged, three great powers competed for control of the sea-lanes across the entire length of the Mediterranean: the Phoenicians of the Levant; the Etruscans, who emerged in Italy and provided the first kings of Rome, but whose provenance remains mysterious to the present day; and the classic Greek city-states, which ultimately became the cradle of modern Western civilization. Of these, the earliest to rise were the Semitic Phoenicians, who left the West their modern alphabet.

The Phoenicians had two advantageous assets to launch their Mediterranean seafaring career: good harbors at Tyre, Sidon, and Byblos and abundant cedar and other wood resources for shipbuilding and export from Levantine forests that were greatly coveted by great powers in Mesopotamia and Egypt. From 1000 to 800 BC, Phoenician traders had the Mediterranean virtually to themselves. Phoenician ports were crowded with large cargo ships. They created one of the most daring seafaring trade societies in history. On their long sea voyages, Phoenicians even sailed by night and ventured far out of sight from the coasts. They established great colonies across the Mediterranean, including at Carthage at the southern gateway to the western Mediterranean near modern Tunis. They sailed through the Pillars of Hercules into the Atlantic Ocean to set up a settlement at the fine harbor at Gades, modern Cádiz in Spain. Thanks to their blockading grip over the strategic Pillars of Hercules from the late sixth century BC, Phoenician vessels for four centuries exploited a virtual trade monopoly in the raw material resources available along Europe’s Atlantic coast and northern seas. Phoenician vessels sailing under commission by Egyptian Pharaoh Neko may have attempted in about 600 BC to circumnavigate Africa by sailing south through the Red Sea, and a century later Phoenicians of Carthage successfully colonized Africa’s west coast—all two millennia before the Portuguese changed world history by accomplishing the circumnavigation feat. For a long while, the Phoenicians’ domestic assets and adventurously earned sea-trading wealth were sufficient to offset their major geostrategic liability of being located adjacent to the powerful land empires of the Near East. After the eighth century BC, however, the Phoenician homeland was overrun by the armies of Assyria and the enduring heart of Punic civilization migrated westward to Carthage.

Where the Phoenicians were first and foremost traders, the loose conglomeration of sovereign Greek city-states that arose by the eighth century BC along the Ionian coasts and neighboring Aegean islands were great colonists. Between 750 and 550 BC, they founded some 250 colonies, including at Syracuse on wheat-growing Sicily and in 658 BC at Byzantium, the future Constantinople and Istanbul, on the Bosporus Strait gateway to the Black Sea and the golden wheat fields of the Crimea on its northern coast. Their economy was initially based on trading their homeland’s highly prized wine and olive oil for basic grains and raw materials, although their comparative advantage gradually diminished as competing colonists transplanted vineyards and olive trees throughout the Mediterranean.

The leading Greek Ionian city-state was Miletus. In the eighth century BC, mariners from Miletus discovered how to reliably navigate during the warm sailing season to the Black Sea through the Hellespont and Bosporus straits, which for much of the year were barred by sudden, racing currents, difficult eddies, and strong northeasterly headwinds. Although the city’s famous harbor has long since silted up, in the seventh and sixth centuries BC, Miletus was the leading trader of goods between the Mediterranean and Black seas. The latter was almost a Milesian lake. Tons of wheat and fish were transshipped from the Black Sea on Milesian vessels, financed by Milesian bankers and traded at great profit to the grain-poor city-states of the Aegean.

The wealth and urbanity of Miletus produced some of the formative thinkers of early Greek civilization, including the renowned father of Greek philosophy, Thales. One of the Seven Wise Men of ancient Greece, Thales was also a mathematician, a statesman, and an astronomer; he famously predicted the total eclipse of the Sun of May 25, 585 BC. Thales philosophized that there was a single primal substance of all things—water. Observing water’s protean forms—ice, liquid, and gas—and natural processes, such as evaporation, in which water seemed to turn into air, rainfall where water appeared out of air, the ongoing silting up of river mouths, and the existence of freshwater springs that bubbled up out of the ground, he reasoned that everything on Earth was a manifestation of water in some transformed aspect. Later Greek philosophers such as Aristotle downgraded water to only one of four primary elements—water, air, fire, and earth. Thales’ hypothesis of water’s primacy, which had a parallel in early Babylonian cosmology’s placement of water as the first element of creation, left a profound imprint on Greek thinking in which reason and scientific observation became an exalted means to knowledge.

Miletus also played an instigating political role in the events that culminated in the rise of Athens and the most celebrated flowering of Greek civilization in the fifth century BC. By the mid-sixth century BC, the land-based Persian Empire founded by Cyrus the Great had gained hegemony over much of Asia Minor, including Ionia. In 499 BC, following a series of intrigues, Miletus led a rebellion of Ionian Greek cities against Persian overlordship. It enlisted the alliance of Athens, which sent a few ships across the Aegean to assist. Within five years King Darius’s Persian army crushed the rebellion and ransacked troublemaking Miletus. In 490 BC Darius sent a modest fleet of Persian soldiers to punish tiny upstart Athens for its complicity. But the plan, which depended upon traitors opening Athens’s gates from inside, failed when the Persians lost a battle upon landing at the plain of Marathon and speedy runners carried the news to Athens some 26 miles away before the regrouped Persian fleet arrived—the genesis of the modern “marathon” race.

When the Persians returned a decade later to exact a crushing revenge on Athens and its allies, Darius’s son, King Xerxes, amassed an overwhelming 180,000- to 360,000-man military force and a 700- to 800-ship naval fleet, most of which it had commandeered from its subject states Egypt, Phoenicia, and Ionian Greece. In the spring of 480 BC, Xerxes’ army crossed the Hellespont on two bridges constructed of boats that they lashed together. To avoid a march through rugged mountains, the Persian soldiers painstakingly dug a canal through the Athos peninsula. As it marched, the army was sustained by seaborne supplies previously stocked at depots along the northern coast of Greece and on its accompanying fleet.

All but some 20 Greek cities surrendered without a fight to the advancing Persians. Panicked Athenians consulted the oracle at Delphi, which in its usual enigmatic manner advised putting their faith in their wooden walls. No one knew whether this meant the traditional fortifications at the Acropolis or the hulls of the naval fleet it had built in preparation for the Persian invasion at the clever politicking of its brilliant young leader, Themistocles. Three years earlier, the forty-four-year-old Themistocles had persuaded Athens’s democratic assembly to invest the windfall from a recent discovery at a state-owned silver mine in a modern naval fleet that could attack Persia’s weak point—its extended naval supply lines—rather than relying upon the traditional army. When a small, valiant force of Spartans and Athenians were finally defeated by the advancing Persians at the mountain pass at Thermopylae to open the road to Athens, Themistocles made his decision. He ordered the evacuation of Athens, which the Persians proceeded to ransack and burn, while he retreated with his navy. Xerxes pursued, intent on destroying it, lest it retain the potential to disrupt Persian supply lines and command of the Aegean. At a narrow channel between Salamis Island and the mainland just west of Athens, the Persian fleet caught up to the Greeks.

On the morning of September 23, 480 BC, Xerxes ascended a hillside and, from a majestic throne, sat back to watch history’s first recorded major sea battle, which he confidently expected to culminate with the utter demolition of the Greek navy. In the three-mile-long and one-mile-wide sound below him he could see the entire Greek fleet of 370 ships bottled up at either end by his own fleet, which had twice as many warships. Yet unbeknownst to Xerxes, Themistocles had consciously enticed the Persians to fight the showdown battle inside the confined waters at Salamis.

Although his ships were fewer in number, Themistocles’ navy consisted of newly designed triremes, one of the great warships of history. With three banks of oars manned by 170 oarsmen who rowed with their backs to the direction they traveled, the trireme lay low in the water and had vastly more power than the traditional, two-banked, 50-oared, 100-foot-long Aegean penteconter. Under expert seamanship, it was fast and nimble, able to sprint into battle at nine knots and turn around in one minute in an arc of two and a half ship lengths. It had two main weapons: a new, more deadly and readily extricable bronze-tipped ram to punch a hole in the hull of its enemies; and armored marines, who launched projectiles at the enemy ship as the ram closed in and, as necessary, grappled alongside to board for hand-to-hand combat.

Themistocles knew that Greeks could not win a battle in the open seas, where the enemy could deploy its entire fleet of much heavier, slower-moving war galleys. So with great cajoling, he maneuvered his reluctant allied Greek commanders to allow themselves to be entrapped in the strait at Salamis in the hopes of inducing Xerxes’ navy to fight in constricted waters, where their numerical advantage would be diminished and the Athenian-designed triremes’ tactical strengths most exploitable. On the morning of the battle, Themistocles lured the Persian fleet deeper into the narrow strait with a retreating maneuver, then ordered a sudden about-face. His rams charged the bewildered Persian fleet. Many Persian ships foundered, while trailing Persian vessels pressed in upon them from the rear. Almost half the fleet sank. Only about 40 Greek triremes were lost.

With his naval supply lines interdicted, and his land forces suddenly vulnerable, Xerxes expeditiously withdrew much of his army to Asia Minor. Fearful that the Greek fleets might cut off their escape route by destroying the bridge of boats at the Hellespont, the Persians beat a starving, dysentery-racked retreat, in which, by Herodotus’s account, “they gathered the grass that grew in the fields, and stripped the trees, whether cultivated or wild, alike of their bark and of their leaves, and so fed themselves.”

Not only was Greece saved, but Athens’s supremacy on the sea was also established for generations to come. Salamis also was one of the earliest dramatic examples of the asymmetrical advantages of naval power in enabling small, less-populous states in the age of sail to offset the balance-of-power advantage of much-larger, predominantly land-based rivals. At once it enlisted the natural impediment of the sea as a stalwart defensive ally, while conferring formidable, tactical advantages in controlling supply lines, projecting offensive military force, and disruptively blockading enemy ports. Economically, it provided key advantages in transporting and profiting from trade in international goods.

Throughout history, from ancient Greece to the British Empire and the modern era of nuclear-powered navies, naval superiority has always been a key axis of power. Although great battles like Salamis were relatively rare events, by determining control over the seas they often were associated with decisive turning points. In the Mediterranean world, given its absence of strategically dominant inland waterway routes, it has been especially true that empires repeatedly rose and fell on naval sea power. Subsequent sea battles from Rome’s victory over Carthage off Sicily in the First Punic War to the defeat of the Spanish Armada by England in 1588, the Napoleonic War battles of the Nile and Trafalgar in 1798 and 1805 and World War II’s decisive ocean battles involving the Bismarck in the Atlantic and Midway in the Pacific reiterated the early lesson of Salamis.

The Battle of Salamis catapulted Athens, like Minoan Crete before it, into the role of eastern Mediterranean naval and commercial superpower. The rebuilt city-state soon became the wealthy epicenter of a glorious burgeoning of arts, philosophy, rhetoric, politics, history, mathematics, and scientific inquiry that created the foundations of Western civilization. Immediately after Salamis, Athens and the Greek world experienced its classical golden age.

Athens’s turn to naval power at Salamis under Themistocles spurred a democratizing influence as well. It elevated the voice—eventually institutionalized in voting rights—of the large number of poor oarsmen required to man the galleys and diminished the relative influence of the traditional army, which was drawn more heavily from the aristocracy.

Reinforced by Athens’s international free-trade policy, an articulated market economy with safeguarded private property rights evolved. The new Athens did not prosper merely by trading local olive oil and wine to obtain wheat and other vital goods. Its port city, Piraeus, became a thriving international clearinghouse market for goods destined for ports throughout the region. As in Venice, Amsterdam, London, and New York and other great shipping entrepôts of future centuries, a complex of private warehouses, shippers, bankers, wholesalers, and other commercial service suppliers grew up around its docks. A rudimentary commodities market for grain developed, in which a benchmark grain price for the entire Mediterranean was established from the demand and supplies arriving from the Black Sea, Sicily, and Egypt. The government treasury bulged with revenues from the 2 percent toll levied on all cargo using its port. Athens’s democratic citizens’ assembly, in turn, encouraged these burgeoning private markets by improving the port with breakwaters, docks, dredging, and other public services to accommodate more and larger ships. To protect its maritime commerce, Athens also provided naval escorts for the grain freighter convoys making the slow journey to Piraeus from the Crimea through the Bosporus and the Hellespont. As the unspoken marriage of convenience between government and private markets yielded rising prosperity and power for both, the democratic base of the Athenian polis became more representative and pluralistic.

Seafaring culture itself further nurtured the evolution of a new model of society based on representative, liberal market democracy for vested citizens. In contrast to the centralized river irrigation and land-oriented hydraulic states in which the populace had few practical economic alternatives other than complying with the policy commands and heavy taxes of the central government, private sea merchants had the natural freedom to trade in harbors where taxes were lower for the services offered and their rights better safeguarded. Thus it was no coincidence that many of history’s leading seafaring trading states were also its leading representative market democracies and shared lineage with the political economic traditions born in Athens. With the rise of Athens, civilization’s great dichotomous tension was joined between the main competing forms of mobilizing economic goods and manpower—by authoritarian government command, on the one hand, and market price signals and private profit incentives on the other—that have competed for supremacy in numerous forms through the ages into the twenty-first century.

Athens’s glory age came to an end when its political ambitions overreached its naval power. It lost the Peloponnesian War when Sparta matched its sea power sufficiently to be able to impose a blockade on its ports to starve it into submission. In 338 BC it submitted to the rising, neighboring northern inland kingdom of Philip of Macedon, who plowed the wealth earned from his introduction of irrigated agriculture in Macedon’s fertile central plain into building an expansive military force capable of controlling the gateway city on the Bosporus, Byzantium, and with it gained a strategic stranglehold over the Greek bread supply coming from the Black Sea. Yet in one of history’s many unforeseeable twists, Athens’s fall to Macedon became the instrument of implanting its Hellenic civilization and Greek language far and wide throughout the Mediterranean and Eurasia. The agent of this brilliant diffusion was Philip’s son, Alexander the Great.

Tutored in Greek civilization as a teenager by no less than Aristotle himself, Alexander came to power as a twenty-year-old in 336 BC upon Philip’s assassination. From the time he led his army of 43,000 soldiers and 6,000 cavalry across the Hellespont two years later to launch his conquest of the Persian Empire, Alexander never lost a single military engagement in a triumphal 15,000-mile, eight-year military march. When he died in 323 BC in Nebuchadrezzar’s palace at Babylon at only thirty-two years of age, he reigned over the expanse of the Old World from the Nile to the Indus. His conquests were a dividing line of ancient history, inspiring later great conquerors from Caesar to Napoléon and instilling a millennium-long flourishing of Greek cultural influence in the western half of the Old World that was ultimately subsumed into Islamic and Christian European civilization.

In creating his empire, Alexander displayed a versatile mastery of the military and civil arts of water management. Although at the outset he had no navy, he understood the paramount strategic importance of controlling the sea-lanes, and he devoted many of his earliest military campaigns to neutralizing his rivals’ naval advantages through unconventional land assaults from the rear that closed all enemy Mediterranean ports throughout Syria, Phoenicia, and Egypt. Turning inland, he hastened to cross the Tigris in 331 BC before his Persian enemy could employ that river barrier in its defensive stand, and then won a decisive victory at Gaugamela, not far from the ancient Assyrian city of Nineveh. Beyond Persia into central Asia and India, Alexander not only overcame armies but also diverse hydrological habitats, including the mountain snows of the Hindu Kush, the turbulent Oxus River, and central Asia’s parched steppes. After crossing the Indus River in the spring of 326, he penetrated victoriously into the Punjab by attacking during the torrential monsoons, a time when Indian troops normally took a hiatus from fighting and conditions rendered their formidable charioteers, archers, and elephant corps less effective.

Already lord of the largest terrestrial empire in history, Alexander now quested to reach “Ocean”—the vast water body Aristotle and other Greek scholars believed surrounded Earth—and gain the enlightenment of knowledge. But when he urged his exhausted soldiers to press forward into the unknown, dense Ganges forests in search of Ocean, they refused to go on. Only this brought Alexander’s stunning conquests to their end. But he determined to use his return to explore the coast of the uncharted Persian Sea and the harsh Gedrosian desert, which no army ever had crossed. A fleet of ships was built and outfitted. Alexander himself barely survived the six-month trip down the Indus River to the sea when an enemy arrow pierced his lung. To convoy his swollen entourage of up to 85,000 troops plus noncombatant camp followers across the Gedrosian desert, the army dug wells to provide water for itself and the ships, which stocked a four-month food supply for the army. As water supplies dwindled after mountain barriers forced Alexander to turn inland, however, the journey became a march of desperation. Alexander turned it into an opportunity for inspirational leadership. Like a common soldier he marched on foot. When a soldier found a small water source and brought the first drink in his helmet to his king, Alexander first asked whether there was enough for all the troops; upon being told “no,” he dramatically poured out the water and announced he would wait until all his men could slake their thirst before drinking. Up to 25,000 are believed to have perished on the march.

Less than two years later, in June 323 BC, Alexander himself died of a fever at the end of a long night of banqueting at Nebuchadrezzar’s old palace in Babylon. With him died his master plan to rebuild the famous city as the capital of his new Hellenic empire. Yet his legacy flourished through the Greek civilization that took root in the vigorous rebuilding he and his successors undertook wherever they had conquered. Declining irrigation systems in Egypt and Mesopotamia were rejuvenated and expanded with Greek hydraulic engineering, resulting in blossoming production, wealth, and the civilized arts. Ports and harbors were upgraded, and shipbuilding expanded in the Levant. Wherever Alexander passed he founded new cities—many named Alexandria. His most enduring legacy was Egypt’s Alexandria, a splendid seaport and capital city for the 1,000 years of Hellenic and Roman rule. Within a century of its founding, Alexandria became the Mediterranean’s most vibrant entrepôt and the heart of a Hellenic renaissance that was transmitted, through Rome and Islam, to Western civilization. Alexander personally selected the site because of its good anchorage and ample freshwater from a nearby lake, and designed the master plan for the city. To illuminate the way for toll-paying ships into its famous deep, double harbor, his successors erected one of the Seven Wonders of the World, the towering lighthouse at Pharos—probably taller than the Statue of Liberty in New York harbor—whose bronze mirror reflected sunlight by day and fire by night some 35 miles distant. Alexandria’s world-famous library, built by copying all manuscripts that came into its busy harbor, became the central repository for much of the ancient world’s literature and knowledge. In its heyday from 306 BC to the fire of 47 BC, it held as many as 700,000 items.

Greek science, mathematics, and medicine, a research institute, and an observatory flourished anew in Alexandria. Archimedes of Syracuse, the great mathematician, inventor, and father of hydrostatics, studied in Alexandria. In addition to the achievements of Euclid, Plotinus, Ptolemy, and Eratosthenes, Ctesibius, a contemporary of Archimedes, invented a floating mechanism of reliable regularity to calibrate the important water clock, or klepsydra (“time thief”), as well as a hydraulic organ. In the first century AD, Hero of Alexandria invented, as an amusement, a working miniature model of a steam engine—had he been motivated to build a full-scale working version, the world might have had the steam engine some 17 centuries before James Watt applied the same scientific principles to the machines that launched the Industrial Revolution.

It was also from Alexandria in the late second century BC that Greek sailors operating in the Red Sea made the breakthrough discovery of how to navigate the two-way monsoonal ocean winds to sail directly between the Gulf of Aden and southern India and thus projected themselves more prominently into the growing long-distance Indian Ocean trade between Orient and Occident that played such a dynamic role in early world history. In Roman times, Alexandria became the major harbor for exporting Egypt’s indispensable grain surpluses to the imperial Italian capital. To Islam, it bequeathed a seafaring culture. In the Middle Ages, the Alexandria-Venice nexus reigned as the Mediterranean’s premier commercial hub and a vibrant interface between Islamic and Western civilizations.

For several centuries, Alexander’s own embalmed and perfumed body lay in state in Alexandria in a resplendent sarcophagus with transparent cover. No less than Julius Caesar came to pay homage. It survived for two centuries after suzerainty of Egypt passed to Rome in 30 BC.

Rome was the first great power to dominate the entire Mediterranean. Located at the sea’s midpoint, it was strategically well positioned to enrich itself both from the natural resources of the western basin and the vibrant markets and know-how of its advanced, civilized eastern half. For several centuries it derived wealth and power by ruling over its sea routes with an authority reminiscent of the control hydraulic-irrigation societies had exerted over their great rivers.

Although deservedly famous for its great armies, Rome’s rise as a superpower actually began in the third century BC when it seized command of the western Mediterranean’s sea-lanes. Its unique genius as a civilization, indeed, resided in combining its military power with its pragmatic, well-organized, and large-scale applications of engineering technologies—the control and use of water prominent among them. Through water engineering, Rome mastered shipbuilding and seafaring infrastructures for its navy, drainage for the imperial highways used by its army, and construction of massive aqueducts and urban water systems to create something new in civilization—the giant metropolis.

By legend, the city’s founders were the semidivine twins Romulus and Remus, who, like their predecessors Sargon and Moses, had been set afloat to the fates in the river. They had been nursed by a she-wolf (still the city’s emblem) who happened upon them at the Tiber River shoreline, reared by a shepherd, and eventually set up an original settlement on the Palatine Hill near the river. Historical Rome, indeed, commenced with separate tribal settlements atop its famous seven spring-fed hills near where an ancient salt trade route crossed a shallow fording point in the Tiber near the Tiber Island. By the eighth century BC, the city came under the rule of the Etruscans, from whom Rome inherited many of its advanced hydraulic arts of drainage and irrigation. By draining large swamps from Tuscany to Naples and embanking the silt-rich Po River against uncontrolled flooding, the Etruscans made Italy’s limited agricultural resources yield enough food to sustain a pre–Athenian age civilization sufficiently prosperous to challenge Carthage and the Greek colonies of the mid-Mediterranean.

It was under Etruscan rule that Rome’s first large engineering work was completed in the sixth century BC. The Cloaca Maxima, or great sewer, drained the swampy, malarial valley between the city’s Seven Hills to create what became the center of ancient Rome’s civic and commercial life, its Forum. So well constructed that it still functions today, its egress point into the Tiber can be seen along the embankment from the Tiber Island bridge and its malodorous effluvia smelled through the air vents in the Forum’s ruins.

The Romans cast off their Etruscan kings in 509 BC. They set up, like their ancient Athenian contemporaries, an aristocratic republic. Governed by two annually elected consuls, a Senate, and landed patrician families, the Roman Republic would endure in form and as an ideal for centuries. It protected private property and other rights with written law and exalted the virtues of the simple, independent citizen-farmer who was expected to put down his hoe and pick up his arms when war necessitated—ideals extolled in the late eighteenth century by America’s founding fathers. Without the existence of a central, arterial river to provide transport and large-scale irrigation through the Italian peninsula, Rome’s economic and political power consolidated slowly, facilitated by its construction of a network of well-drained major roads that fanned out from the capital in all directions, starting with the southeasterly Appian Way in 312 BC. Rome’s rise was abetted indirectly by the sea power of the Greeks of Syracuse, who early in the fifth century destroyed Etruscan naval power. By 270 BC Rome controlled the entire Italian peninsula. Across the Strait of Messina, on the northeastern tip of the rich, grain-growing island of Sicily, Rome’s expanding ambitions collided with the great Mediterranean naval empire founded by the Phoenicians centuries earlier—Carthage.

The turning point of Rome’s rise in history as a great power was its three Punic Wars, through which it won command of the Mediterranean. The First Punic War began in 264 BC and lasted twenty-three years. Rome’s initial objective was simply to remove Carthaginian garrisons from eastern Sicily. But its besieging armies were frustrated by the resupplies Carthage delivered from its western Sicily strongholds, which in turn were supplied by sea from its capital city in North Africa. Thus, to neutralize eastern Sicily, Rome needed to control the sea-lanes around the island.

Yet Rome at this point was exclusively a land power. To achieve its objectives, it would have to become one of history’s rare land-based civilizations that successfully transformed itself into a dominant sea power as well. In 260 BC the Senate authorized the construction of 20 triremes and 100 quinqueremes, five-bankers manned by 300 oarsmen. Since Romans didn’t know how to design a war galley, they relied upon the know-how of Greeks from the cities of southern Italy and Sicily. In a remarkably few months, with rowing crews training on dry land all the while, the neophyte fleet, with more than 30,000 men, was ready to set sail out of Rome’s harbor at Ostia at the mouth of the Tiber to confront Carthage’s larger, experienced, and redoubtable navy. In effect, the battle for Sicily was to be a proxy contest with Carthage for dominance of the entire western Mediterranean. Rome’s warships did not try to match Carthage’s light, fast fleet designed for rapid maneuvers and ramming executed by skilled seamen. Instead, they were designed pragmatically to mobilize the advantage of Rome’s infantry strength by making the sea battle more like a land fight. They were heavier, slower, and steadier in bad weather, with large decks to hold more marines. They were designed to pull alongside with grapples and board the enemy for hand-to-hand combat. A brilliant stroke was added when the fleet was readying for battle in Syracuse—some say at the suggestion of its ingenious resident, Archimedes—to attach an upright 36-foot-long gangplank with a heavy spike at the outboard that could swing down over the bow and embed sturdily into the nearing enemy vessel both to frustrate its ram and to permit swift boarding by Roman soldiers.

Against improbable odds, Rome’s navy triumphed in the war’s first major sea battle in August 260 BC off Sicily’s northern shore near Mylae. What followed was nineteen years of naval-warfare attrition, both from losses inflicted by the enemy and even larger losses wrought by sea storms. One Sicilian storm in 255 BC cost hundreds of Roman ships and more than 100,000 lives; another two years later off southern Italy sank most of the navy’s rebuilt fleet. In the end, Rome won the First Punic War chiefly by its relentless perseverance in rebuilding its fleet and its tolerance for sustaining heavy losses in vessels and manpower, all the while improving its seamen’s skills. The final battle was at the western tip of Sicily near the Aegates Islands on March 10, 241 BC.

The strategic advantage won by Rome in the First Punic War—of being the most potent naval force in the western Mediterranean—proved to be decisive in the outcome of the Second Punic War, from 218 to 201 BC. It was during the second war that Carthage’s brilliant general Hannibal famously led his army and a contingent of elephants from his base in Spain across the Ebro River into Gaul, over the Alps, and into Italy, where he marauded victoriously throughout the Italian countryside for over a decade in what proved to be a fruitless bid to trigger local insurrection against Roman rule. In the end Hannibal was unable to sustain his supply lines without naval replenishment and was ultimately defeated on the banks of the Metaurus River in 207 BC, when reinforcement troops traveling overland under his brother Hasdrubal failed to arrive in time. Indeed, it was Rome’s naval superiority that had compelled Hannibal to attempt the treacherous overland invasion of Italy in the first place. Had Hannibal been able to go “by the sea, he would not have lost thirty-three thousand out of the sixty thousand veteran soldiers with whom he started,” concluded Captain A. T. Mahan in his classic The Influence of Sea Power upon History. Sea-power superiority also delivered Rome the means to counterattack Carthage. Through the naval supply buildup of a formidable army base in northern Spain, it besieged and finally took Carthage’s Spanish stronghold at Cartagena (“New Carthage”), and then forced Carthage’s surrender in 202 BC through attacks on its North African homeland across the Mediterranean.

The first two Punic Wars transformed the trajectory of Roman history. The conversion of the entire western Mediterranean basin into an unchallenged Roman lake brought Rome its first taste of the fruits of ruling a provincial empire and propelled its rise as one of history’s great powers. All the grain wealth of Sicily, the mineral deposits of southern Spain, the tin, silver, and other resources that moved from the Atlantic through the Pillars of Hercules, and slave manpower from defeated populations came into Roman hands. Gradually, Rome ceased striving for basic self-sufficiency from its low-yielding home soils and began to rely on shipments of imported grain for its daily bread. Large estate owners abandoned drainage projects to reclaim marginal cropland in favor of producing higher-value-added, tradable luxuries like olives, wine, and livestock, often with slave labor. Class tensions polarized as wealth became concentrated in fewer hands, while individual military commanders compensated by advancing the interests of free commoners, who increasingly served as their professional troops.

Initially, Rome took uneasily to its changing political cultural identity as a hegemonic maritime power. Only gradually during the course of the second century BC did it accept the inexorable demands of its success to extend its dominance over the eastern Mediterranean as well. Nevertheless, whenever possible, it exerted its weighty influence indirectly through the soft power of financing trade and being the largest import market, while leaving naval patrol duties in the east to maritime allies like Rhodes and Pergamum. As late as 100 BC, Rome had scaled back its fleet in the eastern Mediterranean to skeletal size.

All that changed dramatically during the first century BC when pirates began to exploit Rome’s minimal naval presence. The largest group of buccaneers, headquartered in Cilicia on Asia Minor’s rugged southern coast, possessed more than 1,000 ships and a formidable arsenal, and was ruled by a well-organized, hierarchical command. By 70 BC they had become an intolerable nuisance by interfering with vital grain shipments to Rome and by brazenly raiding coastal highways as far away as Italy and kidnapping prominent Roman citizens for ransom. One famous hostage was the young Julius Caesar, who was seized while on a ship bound from Rome to Rhodes, where he was to study law. During his captivity Caesar amicably suggested to his captors that due to his importance, they should double their initial ransom demand—which they readily did—and promised, with equal geniality, that after his release he would return to crucify each and every one of them. In fact, as soon as he was freed, he raised a fleet in Miletus and killed as many as he was able to catch, though as a reward for their decent treatment of him he allowed their throats to be slit before nailing them to the cross.

Gripped by a sense of national crisis at the threat to its food supply, Rome’s Senate finally acted. In 67 BC it commissioned General Pompey to rid the Mediterranean of the pirate menace and invested him with almost unlimited power to accomplish it. In one of the most spectacularly successful naval operations in history, Pompey amassed a force of 500 ships and 120,000 marines and launched a methodical, sector-by-sector sweep of pirate enclaves eastward from Gibraltar. In less than three months, all the pirates were defeated and the buccaneer capital in Cilicia was besieged into submission.

Pompey did not stop there, however. Without authorization from the Senate, he sailed his formidable fleet to the Near East, where he brought Syria, Judaea, and the cities of Antioch and Jerusalem under Roman rule. He returned to Rome in 62 BC as a conquering hero with fearful power, and entered a ruling triumvirate with Caesar and Crassus. Pompey’s naval operations revived Roman sea power and organized it into a permanent naval force. Thereafter, it always would be a crucial component of Rome’s ability to wage war and enforce its will on others. At first, however, it was turned inward upon itself in two decades of bloody civil wars that were ignited on January 11, 49 BC, when Caesar and his army marched across the muddy little Rubicon in northern Italy, which violated the republic’s forbidden boundary line, and amounted to an attempted coup d’état. The ensuing civil war between Caesar and Pompey was fought across the breadth of the entire Mediterranean from Spain to Egypt, with Caesar’s breakout from Pompey’s blockade in the Adriatic playing a major role in his ultimate triumph prior to Pompey’s assassination in Egypt. When Caesar, now dictator for life, himself was murdered at the Senate in Rome on March 15, 44 BC, civil war erupted anew.

Fittingly, the final, decisive battle that ended the civil wars and inaugurated the imperial era was fought at sea, in 31 BC, off the Actium promontory near the Gulf of Corinth in Greece. On one side was the allied force of Caesar’s leading general, Mark Antony, and his lover, Egyptian queen Cleopatra. On the other side was Octavian, later honored by the Senate with the supreme title Augustus Caesar, the young grandnephew and adopted son of Caesar. In command of Octavian’s fleet was his brilliant military commander, lifelong right-hand man, and civic colossus of the Roman Empire in his own right, Marcus Agrippa.

To try to offset his inferiority at sea, Octavian had raised a new navy of 370 ships. Recognizing that his enemy’s more-expert crews and nimbler, more-lethal vessels rendered futile any attacks based on the conventional tactic of ramming, Agrippa, in a stroke of genius reminiscent of Rome’s design innovation of the spiked gangplank in the First Punic War, armed the ships with a new weapon he conceived: a catapult that fired arrows leashed to a rope and tipped with an iron-clawed grapnel that enabled his marines to clutch onto enemy galleys from much farther range than the conventional, hand-thrown grapnel, and pull themselves in by windlasses for hand-to-hand combat. With the help of the catapult grapnel, Agrippa’s fleet won decisive battles off Sicily in 36 BC that reversed Octavian’s waning fortunes and went on to win control of the sea war on the Mediterranean. By the time of Actium, he held enough strategic bases to interdict Egypt’s grain supply freighters, and thus slowly starve Antony’s huge military forces, including its Actium fleet, into submission. At the battle itself, Agrippa enjoyed a numerical warship advantage of 400 to 230. Before the day had ended, Cleopatra and Antony had fled for Egypt, where, a year later, they committed suicide, while Octavian’s Rome seized direct possession of the Mediterranean’s last nominally independent great state and with it the prize of the rich Nile granary.

Octavian acquired the title of Emperor Augustus and prudently consolidated his power by, among other actions, establishing a well-organized, permanent professional navy to police the Mediterranean. Over the next 200 years of the Pax Romana, Rome’s empire was extended from the Atlantic to the Persian Gulf, from North Africa to the northern British Isles, and from central Europe through the Balkans. To secure the frontier against barbarian tribes, naval squadrons controlled some 1,250 miles of natural defensive water barriers, including the Rhine, the Danube, and the Black Sea.

One of Julius Caesar’s unfulfilled visions had been to join the Rhine and Danube rivers by a canal and thus create a navigable, arterial water route through continental Europe’s heart, a Nile of Europe. In the event, the Rhine-Danube boundary remained the defensive frontier between Roman civilization and the barbarian world—an equivalent of China’s Great Wall—and never became the central transport waterway unifying northern and central Europe. In the Middle Ages, the old Rhine-Danube frontier again shaped history as the rough, axial dividing line between Catholic and Protestant Europe. Ultimately, it took 2,000 years, until 1992, for political conditions to be conducive for the completion of the 106-mile-long Rhine-Main-Danube canal linking the North Sea and the Black Sea and helping to integrate Europe into a single economic community.

Augustus famously boasted of his legacy that he had found Rome a city of brick and left it a city of marble. Indeed, under the order established by the Roman Empire, wealth and commerce soared. Goods were sucked in by inexorable political and economic gravity from the empire’s provinces along its rivers and bordering seas—North, Baltic, Black, Red, and Atlantic—toward its ravenous mouth and stomach in the central Mediterranean. In an era where it was difficult to move any large quantities by land, river and sea transport were Rome’s vital lifelines.

At the empire’s height, staples and luxuries poured into its bustling ports from distant foreign civilizations spanning the Old World. Grain that became the daily bread dole for commoners came from Egypt, North Africa, and the Black Sea; the rich and powerful enjoyed wools from Miletus, Egyptian linens, silks from China, Greek honey, peppers, pearls, and gems from India, Syrian glass, marble from Asia Minor, and aromatics from the Horn of Africa and the Arabian Peninsula. The mutual attractive force of trade between Rome and its counterpart empire in the Far East, Han China, increasingly found shipping routes through the narrow Strait of Malacca between the Malaya Peninsula and Sumatra to stimulate a vibrant exchange across the long-distance Indian Ocean highway to give critical mass to the nascent global market economy that took hold in this era. Over a hundred trading ships per year sailed the monsoons for India through the Red Sea, parts of which were patrolled for pirates by the Roman navy. Throughout the Mediterranean, the infrastructures of shipping and trade were improved and expanded. In order for large cargo ships to arrive directly at Rome instead of being transshipped in smaller boats from the natural, deep port near Naples, for example, Emperor Claudius in AD 42 constructed a man-made harbor from the dredged marshes north of Rome that was linked to the Tiber by an artificial canal and towpath; inside the harbor, called simply Portus, was a large lighthouse modeled on Alexandria’s Pharos lighthouse.

Rome earned its economic surplus both from being the center of sea trade and from imperial exploitation of the rich provinces around the Mediterranean rim whose own political economies were increasingly molded to the necessities and pulse beat of the giant Roman metropolis. With some 1 million inhabitants at its height, Rome was far and away the largest city in Western history and would remain so for nearly 2,000 years. Such a size was far more than it could support on local Italian agriculture and industry. Therefore, as Rome grew rich upon the provincial resources on its periphery, it also grew increasingly dependent upon them for its internal stability. During Rome’s zenith, chronically high urban unemployment resulted in a welfare state with up to one-fifth of the often restive population receiving subsidized bread from public storehouses and entertainment at public spectacles—gladiatorial contests, ship races and various games, in venues like the Colosseum and the Circus Maximus. Rome’s basic food security required the reliable importation of about 300,000 tons of grain per year. Two-thirds came from destinations within several days’ sailing. But one-third came from the Nile Valley in Egypt, which was a difficult and dangerous thirty- to sixty-day voyage into the prevailing westerlies. Emperors from Augustus onward thus placed high state priority on protecting the fleet of huge grain ships that crossed the open waters from Alexandria to Rome. Each cargo carrier was up to 180 feet long and 44 feet deep—larger than any ship that crossed the Atlantic until the early nineteenth century. One famous grain cargo ship passenger who voyaged to Rome in AD 62 was the prisoner St. Paul. The Nile became so important as a breadbasket that Egypt was forbidden by edicts to export its grain anywhere else. Egypt’s irrigation was intensified and its cultivated acreage expanded under the Romans, facilitated by a long period of good Nile floods, and even rainfall.

Rome vigorously exploited another of history’s seminal water technologies to help it produce the daily bread for so many hungry soldiers and citizens—waterpower. To grind grain into flour to make bread, Rome built vast numbers of waterwheel-powered gristmills on streams and artificial conduits fed by aqueducts that transmitted the energy captured from the flowing current to turn the wheel and the millstone attached to it. As early as the first century BC, Roman engineers had made the ingenious breakthrough of moving the traditional horizontal waterwheel to a position vertical to the water, and to multiply the power it generated through the use of gearing. Many of the water mills built by Rome to feed army garrisons and cities were impressively large and powerful. The famous fourth century AD Roman water mills at Barbegal near Arles, France, used water forced along a six-mile-long aqueduct to drive eight pairs of wheels. It could grind 10 tons of grain daily. It was in imperial Rome that water-powered mills were transformed from small, household and local community devices into tools of large-scale, centralized bread production. As such, they became key instruments of state power.

Why the Romans never fully exploited the enormous work potential of their own advanced waterwheel techniques beyond grinding bread flour is one of the vexing questions of its history. They possessed sufficient know-how to apply waterwheels to industrial uses, such as driving mechanical saws, fullers’ beaters, tilt hammers, or bellows to heat iron furnaces. But what they may have lacked, given their surplus of expendable slave labor, was the economic incentive to invest in labor-saving mechanization.

One new water engineering technology that Romans did profitably employ was hydraulicking for mining. Hydraulicking used powerful jets of water that were far more productive than manual digging in the hills of Spain to extract the gold used for its coinage and financial system. Roman engineers released water from large tanks erected 400 to 800 feet over the mining site to generate waterpower sufficient to shear away hillsides and break up rock formations that exposed the valuable gold veins. In the mid-nineteenth century, hydraulicking would have its most famous, intensive modern application at the height of the California gold rush.

Although not famed for their technological originality, Romans did use water to make one transformational innovation—concrete—around 200 BC that helped galvanize their rise as a great power. Light, strong, and waterproof, concrete was derived from a process that exploited water’s catalytic properties at several stages by adding it to highly heated limestone. When skillfully produced, the end process yielded a putty adhesive strong enough to bind sand, stone chips, brick dust, and volcanic ash. Before hardening, inexpensive concrete could be poured into molds to produce Rome’s hallmark giant construction projects. One peerless application was the extensive network of aqueducts that enabled Rome to access, convey, and manage prodigious supplies of wholesome freshwater for drinking, bathing, cleaning, and sanitation on a scale exceeding anything realized before in history and without which its giant metropolis would not have been possible. That it amply served the poor as well as the rich was likewise a notable development in the history of civic society. Throughout its empire, Rome’s aqueducts supported the robust health of towns and frontier garrisons whose soldiers’ fitness for battle was a critical element of its army’s superiority. Its mobilization of public water that served all classes established a landmark civic standard embraced later by industrial democratic Western societies.

Freshwater conduits had been in use for centuries before censor Appius Claudius built Rome’s first aqueduct, the 10-mile-long subterranean Aqua Appia, beneath its first major paved roadway, the Appian Way, in 312 BC. Some four hundred years earlier the Assyrians had built their aqueducts augmenting Nineveh’s water supply and Hezekiah had excavated Jerusalem’s secret water tunnel. In 530 BC the Greek island of Samos likewise cut a water tunnel two-thirds of a mile long, while classical Athens had several aqueducts. The technical high point of Hellenist water engineering was the Ionian city of Pergamum’s early second century BC 25-mile-long aqueduct with double and triple terra-cotta piping and a pressurized section that enabled water to cross a low valley and then rise again on the other side against the natural force of gravity.

What distinguished Rome’s public water supply infrastructure was not its originality, but rather its precision, organizational complexity, and grand scale. Spectacular ruins of the famous three-tiered, 160-foot-high arches of southern France’s Pont du Gard, the still partly functioning, narrow-arched aqueduct bridge at Segovia, Spain, and the celebrated Roman baths at Bath in England offer glimpses of Rome’s widespread hydraulic accomplishments. Roman water systems underpinned the empire in southwestern Europe, Germany, North Africa, and Asia Minor, including at Constantinople, the “New Rome” established by Emperor Constantine at Byzantium on the Bosporus in AD 330.

Yet nowhere was Rome’s public water system more influential than in Rome itself. Indeed, Rome’s rapid growth to a grand, astonishingly clean imperial metropolis corresponded closely with its building its 11 aqueducts over five centuries to AD 226, extending 306 miles in total length and delivering a continuous, abundant flow of fresh countryside water from as far away as 57 miles. The aqueducts funneled their mostly spring-fed water through purifying settling and distribution tanks to sustain an urban water network that included 1,352 fountains and basins for drinking, cooking and cleaning, 11 huge imperial baths, 856 free or inexpensive public baths plus numerous, variously priced private ones, and ultimately to underground sewers that constantly flushed the wastewater into the Tiber.

As in all ages from antiquity to the present, the pattern of water distribution read like a map of the society’s underlying power and class structures. Nearly one-fifth of total aqueduct water during the empire’s heyday went to meet the watering needs of patricians’ suburban villas and farms. Inside the city walls, paying private consumers and industries and those granted water rights by the emperor were water-Haves who received another two-fifths of Rome’s freshwater. Public basins and fountains used freely by ordinary people, by contrast, received only 10 percent of total aqueduct water. Nevertheless, like the bread dole, provision of a minimum amount of free water was an essential pillar of the state’s political legitimacy that Roman officials were careful to maintain. The remainder of aqueduct water was allocated to the emperor’s ever-growing demands for public monuments, baths, nautical spectacles, and sundry other public purposes. Rome’s patrician families enjoyed hot and cold indoor running water, sanitary bathrooms, and water closets that were unsurpassed in comfort until modern times. Unlike today’s highly pressurized, enclosed pipe systems, Rome’s aqueducts flowed from their source by natural gravity through precisely sloping gradients maintained over long distances; only in the city was pressurized plumbing employed to raise water to elevated locations. Most of the aqueducts were subterranean. But about 15 percent of the system was above ground and ran along its famous arched structures to maintain its gradient over uneven terrain.

Sustaining and housing a population of 1 million may not seem like much of an accomplishment from the vantage point of the twenty-first century with its megacities. Yet for most of human history cities were unsanitary human death traps of inadequate sewerage and fetid water that bred germs and disease-carrying insects. Athens at its peak was only about one-fifth the size of Rome, and heaped with filth and refuse at its perimeter. In 1800, only six cities in the world had more than half a million people—London, Paris, Beijing, Tokyo, Istanbul, Canton. Despite Rome’s hygienic shortcomings—incomplete urban waste disposal, overcrowded and unsanitary tenements, malaria-infested, surrounding lowlands—the city’s provision of copious amounts of fresh, clean public water washed away so much filth and disease as to constitute an urban sanitary breakthrough unsurpassed until the nineteenth century’s great sanitary awakening in the industrialized West.

Although there are no precise figures in ancient records on how much freshwater was delivered daily, it is widely believed that Roman water availability was stunning by ancient standards and even compared favorably with leading urban centers until modern times—perhaps as much as an average of 150 to 200 gallons per day for each Roman. Moreover, the high quality of the water—the Roman countryside offered some of the best water quality in all Europe, and still does so today—was an easily overlooked historical factor in explaining Rome’s rise and endurance.

Yet it was a universal testimony to water’s perennial economic and human value that even in conditions of relative plenty man constantly desired to have more of it. In an amusing reminder of unchanging human nature, Senator Julius Frontinus, who became Rome’s Water Commissioner in AD 97, in his famous short treatise On the Water Supply of the City of Rome urged harsh punishment for the many water thieves who “have laid hands upon the conduits themselves by penetrating the side walls.”

Frontinus modeled himself, almost reverentially, upon the single most illustrious creator of Rome’s public waterworks—Augustus’s loyal military commander, schoolmate, and virtual coemperor for much of his reign, Marcus Agrippa. In AD 33 Agrippa, acceding to Augustus’s request, assumed the office of aedile and with it responsibility for Rome’s municipal works and services. Actium was two years in the future and Augustus—still known as Octavian—faced waning public support at home with the outcome of the civil war with Mark Antony very much in doubt. A famously self-effacing, plebeian-born protégé of Julius Caesar, Agrippa enjoyed wide popularity with commoners that Augustus lacked. His year-long aedileship would become the most lauded and influential in Roman history. At its start, Rome’s public infrastructure, following years of civil discord and war, lay in a crumbling, neglected state. It ended with revolutionary improvements—on a scale often associated with historic dynastic restorations and renewals of civilization—that not only resurrected Rome’s municipal infrastructure and services but also Augustus’s popularity and much of the political support he needed to overcome Antony, then far removed in Egypt with Cleopatra.

Waterworks were the centerpiece of Agrippa’s urban renewal program. In only one year, largely at his own personal expense, he repaired three old aqueducts, built a new one, and greatly expanded the capacity and distribution reach of the entire system. Some 700 cisterns, 500 fountains, and 130 ornately decorated distribution tanks were also constructed, and 170 free public baths were opened for both men and women. He cleaned out the sewers, famously rowing through the Etruscan-built Cloaca Maxima on an inspection tour. In addition, he put on splendid games, distributed a dole of oil and salt, and on festive occasions offered free barbers.

Rome’s municipal water system became Agrippa’s lifelong passion. In the years after his aedileship, even as he ruled over the eastern half of Augustus’s growing empire, led important military campaigns and was considered a leading successor to the emperor when Augustus fell gravely ill, he acted as the city’s unofficial, permanent water commissioner and spent lavishly from his own funds for the purpose. In 19 BC he built a sixth new voluminous aqueduct, the Virgo, whose water was acclaimed for its purity and coldness, which he used partly to supply Rome’s first large public bath near today’s Pantheon.

The Virgo aqueduct, much of which lay underground, had the historical distinction of being the only line never to completely stop flowing through Rome’s subsequent dark centuries; today, Virgo water flows in Bernini’s famous Quattro Fiumi (Four Rivers) fountain in Piazza Navona and terminates at the Trevi Fountain, where the relief in the left panel shows Agrippa himself supervising the construction of the Virgo with the design plans unscrolled before him. Upon his death in 12 BC, at age fifty-one, he bequeathed his slaves to Rome’s water system maintenance crew. His master water system plan was adopted as the basis of the official imperial water administration created a year after his death by Augustus. It guided Rome’s water management thereafter, including the major new aqueducts built until the early second century. Longer term, Agrippa’s civil works set a standard and concept of public municipal service for all classes, a democratic legitimacy, and tool of exercising political power that is influential in modern liberal Western democracies.

Agrippa’s innovation of the first large public bath—soon magnified in scale, vanity, and variety of activities by the 11 monumental imperial baths erected by succeeding emperors—became the model central institution of social and cultural life in ancient Rome. The traditional Republican era bath was transformed from a simple “sheltered place where the sweaty farmer made himself clean” into a multifaceted, sometimes luxurious “community center and a daily ritual that defined what it meant to be Roman,” writes historian Lewis Mumford. “The Roman bath compares with the modern American shopping center.” A typical Roman’s day at the baths started after a day’s work and lasted several hours. A large facility consisted of a cluster of activity rooms and big bathing chambers surrounding an open, central garden. The richest baths were adorned with statues, floor mosaics, and marble or stucco reliefs on the walls. Bathers generally would first get an oil rubdown in the unctuarium before exercising in one of the gymnasiums. Bathing started in the hot caldarium and steam room or sudatorium, much like a modern Turkish bath, heated by furnaces from below; Romans didn’t use soap, but instead scraped the dirt off their perspiring skin with a curved metal instrument, the strigil. Next, they lounged at length with friends in the tepidarium or warm baths, often conversing and carousing together. Then they dipped in the cold bath, or frigidarium, and swam in the pool. Lastly came a rubdown with oils and perfumes. Along the way they ate snacks and sipped wine served to them by attendants, read books from the bath’s library, got massages, relieved themselves in multiseated latrines along the walls of the baths, and sometimes indulged in drunken carousing and lovemaking. A full range of bathhouses, from free to costly, were available for all classes. At some, men and women bathed naked together, a practice whose repeated banning by emperors testified to its persistence. From one outpost of the empire to the other, Romans reinforced their Roman identity by practicing the daily social and hygienic rituals of the bath.

Just as the high and low floods of the Nile tracked the prosperous and low periods of civilization in Egypt, Rome’s great eras of achievement and population growth corresponded to its periods of aqueduct building and expanding water supply. The early aqueducts were built during Rome’s Italian peninsular expansion as rising population levels overtaxed the city’s resources of local freshwater springs and wells and potable Tiber River water. The transformative victory in the Second Punic War in AD 201 was followed by an intensive burst of Republican era aqueduct building featuring Rome’s third aqueduct, the voluminous, 57-mile-long Aqua Marcia in 144 BC, which for the first time distributed ample good water across the social spectrum. Agrippa’s aqueduct constructions sufficed until the mid-first century AD, when Emperor Claudius increased the water supply by about 60 percent with two new aqueducts, and Trajan added a third in AD 103 to keep pace with the doubling of Rome’s population in the early imperial period. The end of aqueduct construction in the early third century, by contrast, reflected the plague-ridden fall in the city’s population and the early decline of the Western Roman Empire; indeed, the last aqueduct was built in AD 226 mainly to serve the decadent luxury of refurbishing the emperor’s baths rather than the needs of the citizenry.

Other water-related depredations also marked Rome’s decline. Rome’s heavily fortified European frontier river barriers were breeched by Germanic barbarians: In AD 251 the Goths crossed the Danube; in AD 256 the Franks broke through the Rhine. Both pillaged deep into the empire. In the same period Rome began to lose control of the seas and the security of its food and raw material lifelines to its provinces came under steady assault by pirates, Goths, and other barbarian tribes. Rome’s underfinanced and diminished navy increasingly retreated. Hyperinflation, heavy taxation, recession, and severe pestilential disease debilitated the empire’s economy from within. Without, new defensive walls were erected around the capital by Emperor Aurelian in AD 271.

Although the empire earned a temporary, century-long reprieve through the administrative reforms, reassertion of military power, and authoritarian economic command of several resourceful soldier-emperors, notably among them Diocletian and Constantine, its command of the sea-lanes and defenses that underpinned its control of vital supplies from its provinces was irreparably breaking down. This was importantly illustrated in its Egyptian breadbasket. In response to onerous taxation payable in grain—tax “rates” were calculated by Roman governors according to the Nile’s annual flood level—cultivated cropland in Egypt by the third century had shrunk by half as its farmers grew weary of working for overlords and abandoned their fields. Draconian new grain taxes imposed in AD 313 worsened the long-term situation. Finally, in AD 330 Emperor Constantine transferred the capital itself to a new, more defensible and economically strategic location at the ancient Greek city of Byzantium overlooking the Bosporus Strait gateway to the Black Sea. The regular Rome-bound Egyptian grain shuttles were redirected to the “New Rome,” renamed Constantinople. Rome’s remaining population was left to fend for itself. As often in history, the change in main water transport routes signaled the shift in destinies among leading powers and civilizations.

The Western Roman Empire’s final demise accelerated in the late fourth century AD. The proximate cause was a new wave of incursions by Gothic and other barbarian tribes put to flight by the invasion into eastern Europe from the central Asian steppes of a fearsome, nomadic tribe, the Huns. The Huns, who eventually settled in the Danube valley, themselves had been propelled into motion by their own ejection from their Asian homelands by an even more warlike group, the Mongolian Juan-juan war confederacy, which also constantly menaced China. By AD 410, when traitors opened Rome’s gates to Alaric, the Visigoth leader, for the traditional three days of sacking, the imperial Western seat of its government already had fled to safety at Ravenna, where the mucky coastal marshlands afforded better natural defenses from cavalry and barbarian armies.

Rome’s aqueducts also figured prominently in the city’s subsequent history and its ultimate renaissance as a center of world civilization. In the mid-sixth century, Byzantine Roman emperor Justinian made a major effort at revival when he tried to retake Italy from the Goths. The Eastern Empire had prospered from its seat at Constantinople and even had launched a formidable new navy. Justinian assigned the exceptionally talented general Belisarius to undertake the recovery of Italy. In 536 and 537, Belisarius successfully conquered northward from Sicily, took Naples by sending 400 soldiers undetected through an aqueduct he had drained during the siege, and then entered Rome without a fight when the Goths evacuated it as indefensible. Destroying Rome’s aqueducts was one of the first targets of the Goths in their countersiege against Belisarius. Water ceased to flow almost everywhere; baths, drinking fountains, basins, and sewers went dry. Citizens were forced to crowd into the low-lying areas closer to the Tiber and rely upon the river and wells for their freshwater. The cutoff of the aqueduct flow also shut down the big waterwheel-powered gristmills on the Janiculum, the steep hill near the modern Vatican where much of the city’s daily bread was produced. The ever-resourceful Belisarius responded by constructing floating water mills, moored between two rows of boats, under the Tiber bridges where the currents are artificially accelerated—such floating water mills later became commonplace under medieval European city bridges. The Goths tried to jam or break the waterwheels by throwing the bodies of slain Roman soldiers and tree trunks into the Tiber, but Belisarius thwarted them by laying a protective chain across the river to catch the debris.

The Goths also secretly probed the empty aqueduct channels in the hopes of gaining surprise entry into the city. They might have succeeded had not a Roman sentry at the Pincio Hill gate glimpsed the flickering torch light of Goth soldiers as they passed a shaft rising to the surface from the subterranean channel of the Aqua Virgo. The sentry concluded he had seen the gleaming eyes of an errant wolf. Belisarius, however, insisted on an investigation that exposed the Goths’ incursion. He ordered the sealing up of all the aqueduct channels. After defending Rome, Belisarius moved north. In AD 540 he took back Ravenna, which the Goths had made their capital. His success and growing popularity, however, made Justinian uneasy about his ambitions. He was recalled. In the end, Justinian’s dreams of imperial restoration scarcely outlived him. A new wave of barbarian invasions, this time led by the Germanic Lombards, soon overwhelmed Italy.

By the end of the sixth century, with most of its aqueducts and sewers in ruins and its buildings crumbling, as Rome biographer Christopher Hibbert describes it, “Rome’s decay was pitiable…the Tiber carried along in its swollen yellow waters dead cattle and snakes; people were dying of starvation in hundreds and the whole population went about in dread of infection…The surrounding fields, undrained, had degenerated into swamps” infested with malaria-bearing mosquitoes. The city’s population had shrunk to only 30,000. An anti-Lombard alliance between the Papal States and the Frankish Carolingians—reaching its apogee in AD 800 with the St. Peter’s Christmas Day coronation of Charlemagne as Holy Roman Emperor—and a papal effort to marshal peasant labor to repair some of the aqueducts failed to endure. By 846 Muslim pirate vessels traveled up the Tiber and plundered St. Peter’s.

The Mediterranean West’s free-market seafaring and republican democratic traditions, however, were not totally extinguished on the Italian peninsula. Instead, they were transplanted after AD 400 to a cluster of islands in a very shallow 200-square-mile saltwater lagoon intersected by a few deep channels at the head of the Adriatic Sea to which prosperous Roman citizens from the countryside had fled for safety from the barbarian marauders. Venice was destined to become the most precocious of the early Italian city-states, the preeminent sea trading and naval power in the Mediterranean, a progenitor of the modern market economy and the longest lived democratic republic in world history. By AD 466 the dozen tiny island communities began to elect representative tribunes to coordinate affairs among themselves. The first doge, or duke, was elected ruler in AD 697 in what would be an unbroken line of democratically chosen successors until the Venetian republic was finally overrun 1,100 years later in 1797 by French conqueror Napoléon Bonaparte.

Venice lent its nascent naval power in the Adriatic to assist Belisarius and the Byzantine Empire, in what would become a long, complex, competitive alliance between the two greatest sea powers of Christian civilization in a Mediterranean soon threatened by the ascendant commercial and military forces of Islam. It was through Venice that the historic bridge of continuity was established between the early republican seafaring trading traditions born in the ancient Mediterranean and the sea-oriented, liberal market democracies that later rose to world preeminence in post-Renaissance western Europe.

The revival of the city of Rome itself began in 1417 with the end of the Great Schism and the return of the reunified papacy to Rome in the person of Martin V. For want of drinking water, much of Rome’s population at the time was still clustered in ramshackle houses close to the filthy Tiber. One of Martin’s earliest acts upon returning to Rome was to repair the still partly functioning Virgo Aqueduct that had eluded total destruction by the Goths. Over the next two centuries, several of Martin’s successors, notably including Nicholas V, Gregory XIII, Sixtus V, and Paul V—known collectively to historians as the “Water Popes”—dedicated themselves to rebuilding Rome’s water system and adorning it with the high Renaissance fountains still admired today. As the water returned, so did Rome’s population and the city’s grandeur. Rome’s population doubled to 80,000 by 1563, reached 150,000 in 1709, and rose to 200,000 by the time of the birth of the Italian state around 1870. Fittingly, the last pope before Rome’s integration into democratic Italy completed the redesign of the Republican-era Marcia aqueduct, which became Rome’s first to operate under modern-era pressure with pumps.