A More Perfect Heaven: How Copernicus Revolutionized the Cosmos - Dava Sobel (2011)

Part I. Prelude

Chapter 4. On the Method of Minting Money

Coinage is imprinted gold or silver, by which the prices of things bought and sold are reckoned according to the regulations of any State or its ruler. It is therefore a measure of values. A measure, however, must always preserve a fixed and constant standard. Otherwise, public order is necessarily disturbed, with buyers and sellers being cheated in many ways, just as if the yard, bushel, or pound did not maintain an invariable magnitude.


The canons fled the torched city of Frauenburg for temporary shelter in Danzig, Elbing, and Allenstein. Copernicus perforce returned to the heavily fortified castle he had so recently vacated. The new administrator, Jan Krapitz, welcomed him there, happy to have such an experienced diplomat by his side in a time of war. But each month brought more terrible news to the canons trapped at Allenstein, as Albrecht’s armies swarmed over Varmia. Copernicus, resuming the office of chancellor, composed letters to the king to request arms and men for defense. He directed these pleas first to Heilsberg, where Bishop Fabian signed them and sent them on to Sigismund in Krakow. Sometimes the enemy intercepted the desperate correspondence, and sometimes the king received it but could not comply. Even when he responded with reinforcements, the new recruits failed to rout the knights.

Confined to the castle, Copernicus continued the planetary observations that clarified his picture of the universe. On February 19, 1520, his forty-seventh birthday, he judged Jupiter, at 6:00 A.M., to be 4°3’ to the west of “the first, brighter star in the forehead of the Scorpion.” Sometime in the spring, Jupiter would reach its annual opposition, to appear exactly opposite the Sun in Earth’s skies. No one could see both bodies at once when that happened, but an experienced practitioner might fix the time by combining predictions from theory with observations over a period of months. Having thus begun his watch in February, Copernicus marked the moment of opposition at 11:00 A.M. on April 30. Jupiter was then moving in reverse, or “retrograde,” as though backing away from the Scorpion’s sting—and also making its closest approach to Earth. While other astronomers viewed the timing of these several events as coincidence, Copernicus linked them inextricably together as the consequence of planetary order: The Earth, being closer to the Sun, overtook the slower Jupiter once per year. In passing, it left the Sun to one side and Jupiter on the other, coming as close to Jupiter as ever it could. Jupiter itself never changed the direction of its movement at such times, but merely appeared to do so to observers on Earth as they sped by. The same logic governed the annual opposition of Saturn, which Copernicus tagged a few months later, at noon on July 13.

The movements of Jupiter and Saturn at this juncture raised alarm among astrologers. The two planets were heading toward their “Great Conjunction”—the close heavenly union that they consummated every two decades, always with momentous effects. The popular almanac by Johann Stoeffler and Jacob Pflaum foresaw in the upcoming Great Conjunction of 1524 “changes and transformations for the whole world, for all regions, kingdoms, provinces, states, ranks, beasts, marine animals, and everything that is born of the earth—changes such as we have hardly heard of for centuries before our time, either from historians, or from our elders. Raise your heads accordingly, Christian men.”

On October 19, 1520, a detachment of knights surrounded Bishop Fabian’s palace at Heilsberg and settled in siege there for weeks. Under these circumstances, the chapter turned Jan Krapitz out of office at the November election, though he had served only one year, and drafted Copernicus to replace him. On the day his second stint as administrator started, November 11, restless knights hovered within a day’s ride of Allenstein, where only a hundred of the king’s soldiers stood guard at the gates.

Copernicus filled some of his most anxious hours cataloguing the chapter’s archives, which had been moved to Allenstein over the years for safer keeping inside the castle treasury. The whole embattled history of the diocese lived in these documents, going all the way back to the bull of Pope Innocent IV in 1243, defining the boundaries of Prussia, and the 1264 parchment on which Anselm, the first Bishop of Varmia, envisioned the raising of a great cathedral at Frauenburg. The several hundred items—bulls, treaties, grants, deeds, wills, testimonials, petitions—filled a chest of many drawers. Even as Copernicus sifted and re-sorted the legal materials with their ornate official seals, he wrote new letters of appeal, begging King Sigismund to bolster the forces protecting Allenstein’s repository:

“Most Gracious Prince and Lord, Sigismund, by the Grace of God King of Poland, Grand Duke of Lithuania, Sovereign and Hereditary Lord of Ruthenia and Prussia, and our Most Gracious Lord,” Copernicus addressed His Majesty on November 16. He described the awful details of the previous day’s invasion of the nearby city of Gutstadt, now fallen to the knights, and expressed his willingness to die—as it seemed likely he would—in defense of Allenstein.

“For we are desirous to do what befits noble and honest persons, who are completely devoted to Your Majesty, even if we had to perish. All our possessions and ourselves we commend and entrust to Your Majesty’s care.” Meanwhile he continued methodically to list those possessions: “Document concerning the transfer of the head of St. George from Heilsberg to Frauenburg Cathedral,” “Document of the king of France concerning a gift of wood from the Holy Cross.”


In this 1520 painting by Stanisław Samostrzelnik, King Sigismund kneels beside the Bishop of Krakow to be blessed by St. Stanislaw, the patron saint of Poland.

Sigismund’s infantry marched in at the end of November. The Varmia canons took little comfort from the presence of the troops, however, and abandoned the castle in terror. Only Copernicus and Canon Henryk Snellenberg stood their ground at Allenstein. They were there when the king’s cavalry arrived in December, and even then the two canons did not relax their vigil. They faced their greatest test in January 1521, when Albrecht and an expanded army of his order demanded the castle’s surrender. But then, in a sudden reversal, Albrecht merely ransacked the nearby villages and withdrew homeward toward Königsberg, having agreed to a provisional cease-fire. Still Copernicus would not stop shoring up the castle’s defenses. He procured cartloads of the long guns called harquebuses from Elbing, and lead for shot, and food, and salt. Ready now for any sort of escalation, he received word of the April 5 treaty, signed in Torun, declaring a four-year truce.

Peace put Copernicus briefly back to work on the more mundane matters of administration. In May 1521 he oversaw the reassignment of land parcels made vacant “by the death of Michel the one-eyed,” “by the beheading of Peter in Hoensteyn for plotting treason,” and for a variety of other reasons. Both the peasants and the land had suffered war losses.

In June the chapter called Copernicus back to Frauenburg to restore normal order in the north, while his capable friend Tiedemann Giese took over at Allenstein. Giese’s new term as administrator—this was his third—proved the most difficult of his career. Despite the peace treaty, the knights continued laying waste to Varmia. And yet, because of the peace treaty, the chapter could not fight back. Giese wrote petitions for redress of grievances. He made impassioned appeals for peaceful relations at summit meetings between the Prussian Estates and the Teutonic Order. Nothing, it seemed, would dislodge the knights from the city and environs of Braunsberg, which they had occupied since the start of the recent war. Still Giese persisted in his negotiations. Both the king and the bishop promised to support him at the summit planned for Graudenz in March 1522. Sigismund would send his emissaries, and Fabian would attend in person. In the event, however, the bishop was too ill to leave his bed, so he sent his physician, Doctor Nicolaus, in his stead.

Copernicus joined Giese in Graudenz, only slightly delayed by flooded bridges over the River Bauda that all but barred his way out of Frauenburg. On March 18, he stood with Giese before the assembled representatives and seconded his enumeration of the knights’ abuses. Three days later, he delivered the treatise on coinage that he had conceived before the war, chastising the minting practices that had sent the currency into free fall.

“The worst mistake,” he charged, “which is absolutely unbearable,” is for the government to mint new coins—of inferior intrinsic worth, though pretending to equal value—while the old coins are allowed to remain in circulation. “The later coinage, always inferior in value to the earlier coinage, … constantly depressed the market value of the previous coinage, and drove it out.”2

Copernicus compared the infusion of inferior coinage to the sowing of bad seed by a stingy farmer. The government, like the farmer, would reap exactly what it sowed, he said, since its practices damaged the currency as surely as blight ruined grain.

“Such grave evils, then, beset Prussian money and, because of it, the whole country,” he continued. “Its calamities and decline benefit only the goldsmiths, who take the value of the money into their own hands.”

To remedy the situation—“before a greater disaster!”—Copernicus recommended a consolidation of the mints, so that “only one place should be designated for the minting of money, not for a single city or under its emblem, but for the entire country.” Mint no new money in the interim, he further counseled, and above all set strict limits for the number of marks to be struck from a single pound of fine silver. Then, as soon as the new currency is introduced, prohibit the use of the old, so as to force the surrender of outdated coins for new ones—at a loss, yes, but only a slight one. “For, this loss will have to be suffered once, in order that it may be followed by many benefits and a lasting advantage, and that a single currency reform in 25 or more years may be enough.”

His suggestions sounded even more relevant now that Sigismund wished to unify the disparate currencies of his kingdom. In order for the Polish Crown coins and Prussian monetary systems to be reconciled, a firm rate of exchange had to be established among them. Copernicus immediately produced an addendum to his treatise while still at the March 1522 meeting, outlining a specific plan to equalize the currencies. But the assembly ended without changing the status quo, either of coins in the realm or the knights ensconced in Varmia.

Grand Master Albrecht had condoned the minting of inferior Prussian coins from the moment he took over the Teutonic Order in 1511. Nevertheless, the high cost of war had put him on the brink of bankruptcy. Albrecht betook himself to Germany in 1522 to attend the Diet of Nuremberg, where he hoped to acquire new allies—and sufficient cause to break the peace with Poland. At the Diet, Albrecht met one of Martin Luther’s disciples, a former Catholic priest named Andreas Osiander. As an avowed convert to the new evangelical Lutheran faith, Osiander set about convincing Albrecht to convert as well. Albrecht then went to Wittenberg to seek out Luther for further consultation. The now famous heretic, excommunicated by Leo X in 1521, likewise urged Albrecht to end his allegiance to the Catholic Church—and also his allegiance to the Order of Teutonic Knights. Luther thought it preferable for Albrecht to appropriate the knights’ side of Prussia as his own, find a wife to rule it with him, and raise a family dynasty to inherit his privileges. As Albrecht began to explore these intriguing avenues, his ten-year enemy, Fabian Luzjanski, the Bishop of Varmia, died of syphilis on January 30, 1523.


Coins from the reign of Sigismund I.

Copernicus, who had shunned the easy road to the bishopric that his uncle once paved for him, now found himself presiding at Heilsberg Palace. The chapter chose him to watch over all the lands of the diocese, including those appertaining to the bishop’s see, until Fabian’s successor was installed. Given the rancor that had surrounded the selection process after Bishop Watzenrode’s passing, King Sigismund sent his envoys to Heilsberg in February to foil any preemptive election attempts by the chapter. Copernicus received these men with assurances that the canons would not only honor the king’s right of nomination and approval, but also swear their allegiance to him anew under the next bishop, whosoever that might be.

On April 13, the chapter chose the king’s favorite, Maurycy Ferber. Bishop-elect Ferber, a distant relative of Tiedemann Giese, belonged to a politically powerful family from Danzig, where one of his kinsmen currently served as mayor of the city. Pending papal approval of Ferber, Copernicus acted as de facto bishop all through the spring and summer of 1523. He struggled to restore law and order by ridding the region of recalcitrant knights and the rear guard of the Polish military. The very forces who had come to Varmia’s defense now illegally occupied several villages and fortresses. They refused to leave until the king intervened. Following Sigismund’s orders of July 10, all Polish commanders of troops squatting in the diocese finally relinquished their claims and decamped. The knights, however, remained.

In August the Moon turned red—not as a metaphor for blood or war, but actually and naturally, as the result of a total lunar eclipse. Copernicus noted the first dip of the full Moon into the cone of the Earth’s shadow at “2 and 4/5 hours past midnight,” or 2:48 A.M. on August 26.

Traversing the shadow of the Earth, the Moon dimmed by degrees until fully immersed. Then, instead of disappearing in darkness, the eclipsed Moon daubed itself with the Sun’s color: It glowed like an ember throughout the hour of totality, reflecting all the dusk and dawn light that spilled into Earth’s shadow from the day before and the day ahead.

Copernicus never missed a lunar eclipse. No astronomer let such an opportunity slip, for the Moon in eclipse pinpointed celestial positions as no other phenomenon could. At such times the Earth’s shadow became visible on the Moon’s surface, and the center of that shadow indicated the location of the Sun—180° opposite in celestial longitude. With the Moon’s current coordinates thus confirmed, one could also measure the distances of stars and planets from either the Sun or the Moon. “In this area,” Copernicus remarked, “Nature’s kindliness has been attentive to human desires, inasmuch as the Moon’s place is determined more reliably through its eclipses than through the use of instruments, and without any suspicion of error.”

Even with the help of “Nature’s kindliness,” the tilt of the Moon’s orbit relative to the Earth’s great circle limited the frequency of lunar eclipses to once or at most twice a year, though some years have none. After August 26, there would not be another total lunar eclipse till the end of December 1525.

At the moment of mid-eclipse, which Copernicus recorded on this occasion as 4:25 A.M., the Moon stood at opposition, yet stayed its course straight ahead. Unlike Jupiter or Saturn, the Moon never shifted into reverse at opposition—or ever, at any time—because the Moon, alone among all heavenly bodies, truly did orbit the Earth.

“In expounding on the Moon’s motion,” Copernicus wrote, with no apparent irony, “I do not disagree with the ancients’ belief that it takes place around the Earth.”


Johann Stoeffler’s Calendarium Romanum magnum , published in 1518, predicted eclipses for the years 1518 to 1573. Copernicus annotated his copy with his own observation notes between 1530 and 1541. The special alignment of Earth, Moon, and Sun at eclipse, called syzygy, provided a natural check on celestial positions. Copernicus witnessed both partial and total lunar eclipses, but only partial solar ones. Had he been able to travel to Spain or to the southern extreme of Italy for the April 18, 1539, event, he might have seen the Sun totally eclipsed.

Ptolemy had reported in the Almagest how he derived the Moon’s motion by tracking it through three eclipses of similar duration and geometry. Copernicus was following suit by observing his own three eclipses: one through the midnight hours of October 6–7, 1511; a second more recently, on September 5–6, 1522; and the third in the triad on this night, August 26, 1523. With these data, he meant to reroute the Moon.

On the path Ptolemy had charted centuries earlier, the Moon altered its distance from Earth so dramatically over the course of the month as to make it appear four times larger at its closest approach than at its most distant point. Observers never saw the Moon do anything of the kind, however. Its reliable diameter barely ever changed, yet Ptolemy and most of his followers ignored that glaring fact. Copernicus addressed the discrepancy by offering an alternate course that preserved the Moon’s appearance.

On October 13, Bishop Ferber at last assumed his rightful position, freeing Copernicus to return to Frauenburg. The chapter elections in November named him chancellor once again, but he did not expect the duties of office to impede his astronomical researches or the writing of his book any longer. At fifty, he could only guess how much time remained for those pursuits, before the inevitable loss of his stamina, or his eyesight, or the clarity of his mind.