The Silk Roads: A New History of the World (2016)

3

The Road to a Christian East

In due course, tensions between Rome and Persia abated, and as they did so, attitudes to religion softened. This came about because Rome was forced into retreat so firmly in the fourth century that it found itself fighting for its very life. In a series of campaigns that lasted until Shāpūr II’s death in 379, Persia succeeded in taking key nodes along the trade and communication routes running towards the Mediterranean. Nisibis and Sinagra were recovered, and half of Armenia was annexed. Although this territorial rebalancing helped calm animosities, relations really improved when both Rome and Persia were faced with new challenges: disaster was looming from the steppes.

The world was entering a period of environmental change. In Europe, this was evidenced by rising sea levels and the emergence of malaria in the North Sea region, while in Asia from the start of the fourth century sharply reduced salinity in the Aral Sea, markedly different vegetation on the steppes (evident from high-resolution pollen analyses) and new patterns of glacier advances in the Tian Shan range all show fundamental shifts in global climatic change.¹

The results were devastating, attested by a remarkable letter written by a Sogdian trader in the early fourth century and found not far from Dunhuang in western China. The merchant recounted to his fellow traders that food shortages and famine had taken a heavy toll, that such catastrophe had befallen China as to be barely describable. The Emperor had fled from the capital, setting fire to his palace as he left, while the Sogdian merchant communities were gone, wiped out by starvation and death. Do not bother trying to trade there, the author advised: ‘there is no profit for you to gain from it’. He told of city after city being sacked. The situation was apocalyptic.²

The chaos created the perfect conditions for the mosaic of steppes tribes to consolidate. These peoples inhabited the belts of land linking Mongolia with the plains of central Europe, where control of the best grazing land and of reliable water supply guaranteed considerable political power. One tribe now established themselves as masters on the steppes, crushing all before them. The Sogdian trader referred to the architects of apocalypse in his letter as the xwn. They were the Xiongnu - better known in the west as the Huns.³

Between about 350 and 360 there was a huge wave of migration as tribes were shunted off their lands and driven westwards. This was most likely caused by climate change, which made life on the steppe exceptionally harsh and triggered intense competition for resources. The impact was felt from Bactria in northern Afghanistan right up to the Roman frontier on the Danube, where refugees began to appear in large numbers, begging to be allowed to resettle on imperial territory after being driven off their lands north of the Black Sea by the advancing Huns. The situation quickly became dangerously unstable. A massive Roman army sent to restore order was heavily defeated by the Huns on the flat plains of Thrace in 378, with the Emperor Valens among the many casualties.⁴ The defences burst open, and tribe after tribe poured through into the empire’s western provinces, threatening Rome as a result. Previously, the northern lip of the Black Sea and the steppe lands stretching deep into Asia had been regarded as implacably barbarous, filled with fierce warriors and empty of civilisation or resources. It had not crossed Rome’s mind that these regions could act as arteries, just like the routes linking the west with the east through Persia and through Egypt. These very regions were now about to deliver death and destruction into the very heart of Europe.

Persia was also quaking in the face of cataclysm from the steppes. Its provinces in the east buckled under the onslaught, before collapsing altogether: towns were depopulated; crucial irrigation networks fell into disrepair and broke down as raids took their toll.⁵ Attacks through the Caucasus were overwhelming, and resulted in prisoners and booty being seized from the cities of Mesopotamia, Syria and Asia Minor. Then in 395 a major long-range attack devastated the cities of the Tigris and Euphrates, reaching as far as Ctesiphon, the capital, before finally being driven back.⁶

United by a common interest in repelling the barbarian hordes, Persia and Rome now formed a remarkable alliance. To keep the nomads from descending through the Caucasus, a massive fortified wall was constructed, running for nearly 125 miles between the Caspian and Black Seas, protecting the Persian interior from attack and serving as a physical barrier between the ordered world to the south and the chaos to the north. Studded with thirty forts evenly spaced along its length, the wall was also protected by a canal fifteen feet deep. It was a marvel of architectural planning and engineering, built with standardised bricks made in scores of kilns installed on site. The fortification was manned by some 30,000 troops, housed in garrisons that were set back from the wall itself.⁷ The barrier was just one of several innovative steps taken by the Sasanians to defend Persia’s long northern frontier with the steppe, and to protect vulnerable trading posts such as Merv, which was the first location that would be encountered by attackers coming through the Karakum desert (in what is now Turkmenistan).⁸

Rome not only agreed to make regular financial contributions to the maintenance of this Persian wall, but also, according to several contemporary sources, supplied soldiers to help defend it.⁹ In a sign of how past rivalries had been set to one side, in 402 the Emperor Honorius in Constantinople appointed none other than the Shah to act as guardian to his son and heir.¹⁰

But by that time it was too late - as far as Rome was concerned. Displacement across the steppes north of the Black Sea had created a perfect storm that led to the empire’s frontiers on the Rhine being overwhelmed. A series of raids in the late fourth century cleaved Rome’s western provinces wide open, with tribal leaders gaining personal kudos from military successes as well as material gains that drew in more followers and gave fresh momentum to further attacks. As the imperial army struggled to make a stand against the attacking hordes, one wave after another crashed through the empire’s defences, leading to the devastation of the province of Gaul. Things went from bad to worse when Alaric, a particularly effective and ambitious leader, marched his tribe of Visigoths down through Italy and camped outside Rome to bully the city into buying him off. As the Senate desperately tried to do so, he grew tired of being stalled, and in 410 stormed and sacked the city.¹¹

Shock resonated across the Mediterranean. In Jerusalem, the news was met with disbelief. ‘The speaker’s voice failed, and sobs interrupted his speech,’ wrote St Jerome, ‘the city that had conquered the whole world had itself been conquered … who could believe it? Who could believe that Rome, built up through the ages by the conquest of the world, had fallen, that the mother of nations had become their tomb?’¹² At least the city was not torched, wrote the historian Jordanes with the weary resignation of a century’s hindsight.¹³

Burning or not, Rome’s empire in the west now fell apart. Soon Spain was being ravaged, attacked by tribes such as the Alans, whose homelands lay far away between the Caspian and Black Seas, and whose trade in sable skins had first been carefully charted by commentators writing in China nearly two centuries earlier.¹⁴ Another tribal grouping, the Vandals, who had been displaced by the Huns, reached Roman North Africa by the 420s, taking control of the principal city, Carthage, as well as the vibrant and lucrative surrounding provinces that supplied most of the western half of the empire with corn.¹⁵

As if this were not bad enough, in the middle of the fifth century, having flushed forward a hotch-potch of tribes - Terevingian Goths, Alans, Vandals, Suevi, Gepids, Neurians, Bastarnians and others besides - the Huns themselves appeared in Europe, led by the most famous figure of late antiquity: Attila.¹⁶ The Huns caused pure terror. They are ‘the seedbed of evil’, wrote one Roman writer, and ‘exceedingly savage’. Trained from youth to cope with extreme cold, hunger and thirst, they dressed in the skins of field mice that were stitched together; they would eat roots and raw flesh - which would be partially warmed by being placed between their thighs.¹⁷ They had no interest in agriculture, noted another, and only wanted to steal from their neighbours, enslaving them in the process: they were like wolves.¹⁸ The Huns scarred the cheeks of infant boys when they were born in order to prevent facial hair growing later in life, while they spent so long on horseback that their bodies were grotesquely deformed; they looked like animals standing on their hind legs.¹⁹

Although it is tempting to dismiss such comments as signs of bigotry, examinations of skeletal remains show that the Huns practised artificial cranial deformation on their young, bandaging the skull to flatten the frontal and occipital bones by applying pressure to them. This caused the head to grow in a distinctly pointed manner. It was not just the behaviour of the Huns that was terrifyingly out of the ordinary; so was the way they looked.²⁰

The arrival of the Huns spelt serious danger for the eastern half of the Roman Empire, which had thus far been relatively unscathed by the upheavals that devastated much of Europe. The provinces of Asia Minor, Syria and Palestine and Egypt were still intact, as was the magnificent city of Constantinople. Taking no chances, the Emperor Theodosius II surrounded the city with formidable defences, including a huge set of Land Walls, to protect it from attack.

These walls, and the narrow strip of water separating Europe from Asia, proved to be crucial. After setting himself up just to the north of the Danube, Attila ravaged the Balkans for fifteen years, extracting heavy tribute from the government in Constantinople in return for not advancing further, and securing vast amounts of gold. Having squeezed everything he could from the imperial authorities in terms of ransoms and bribes, he advanced west; eventually his progress was checked, not by the armies of Rome, but by a coalition made up of many long-term enemies of the Huns. At the battle of the Catalaunian Plains, in what is now central France, in 451, Attila was defeated by a large force that included an astonishing array of races drawn from the peoples of the steppes. The Hun leader died not long afterwards on his wedding night - not his first. Celebrating excessively, says one contemporary, he ‘lay down on his back sodden with wine and sleep’, suffered a brain haemorrhage and died in his sleep. ‘Thus drunkenness brought a shameful end to a king who had won glory in war.’²¹

These days, it is voguish to talk of an age of transformation and continuities that followed the sack of Rome - rather than to describe the period as the Dark Ages. And yet, as one modern scholar argues powerfully, the impact of the rape, pillage and anarchy that marked the fifth century as the Goths, Alans, Vandals and Huns rampaged across Europe and North Africa is hard to exaggerate. Literacy levels plummeted; building in stone all but disappeared, a clear sign of collapse of wealth and ambition; long-distance trade that once took pottery from factories in Tunisia as far as Iona in Scotland collapsed, replaced by local markets dealing only with exchange of petty goods; and as measured from pollution in polar ice-caps in Greenland there was a major contraction in smelting work, with levels falling back to those of prehistoric times.²²

Contemporaries struggled to make sense of what, to them, was the complete collapse of the world order. ‘Why does [God] allow us to be weaker and more miserable’ than all these tribal peoples, wailed the fifth-century Christian writer Salvian; ‘why has he allowed us to be conquered by the barbarians? Why does he permit us to be subject to the rule of our enemies?’ The answer, he concluded, was simple: men had sinned and God was punishing them.²³Others reached the opposite conclusion. Rome had been master of the world when it was faithful to its pagan roots, argued Zosimus, the Byzantine historian (who was himself pagan); when it abandoned these and turned to a new faith, it engineered its own demise. This, he said, was not an opinion; it was a fact.²⁴

Rome’s collapse took the sting out of Christianity in Asia. Relations with Persia had improved in the face of their mutual interests in resisting the peoples of the steppe, and with the empire deeply enfeebled Christianity no longer looked as threatening - or perhaps even as convincing - as it had a century earlier, when Constantine was gearing up to attack Persia and liberate its Christian population. In 410, therefore, the first of several meetings took place, prompted by the Shah, Yazdagird I, to formalise the position of the Christian church in Persia and to standardise its beliefs.

As in the west, many divergent views had sprung up about what following Jesus meant precisely, about how believers should live and how they should manifest and practise their faith. As noted earlier, even Kirdīr’s inscription from the third century spoke of two types of Christians, nasraye and kristyone - normally understood as differentiating between locals who had been evangelised and those who had been deported from Roman territory. Variation in practices and doctrine was a constant source of problems, perhaps not surprisingly given that in places like Rev-Ardashīr in Fars, in southern Iran, there were two churches, one conducting services in Greek, the other in Syriac. Rivalry sometimes prompted physical violence, such as in the city of Susiana (in what is now south-western Iran) where rival bishops tried to settle scores over a fist-fight.²⁵ Efforts by the bishop of Seleucia-Ctesiphon, one of the Persian Empire’s most important cities, to bring order and unity to all Christian communities proved frustrating and ineffective.²⁶

With the possibility of salvation depending on getting questions of faith right, it was important to iron out differences once and for all - something the early church fathers had been at pains to stress since the very start.²⁷ ‘I now repeat what I have said before,’ St Paul reminded the Galatians; ‘if anyone preaches a gospel at variance with the gospel which you have received, let him be outcast!’ (Gal. 1:9). It was in this context that texts were written to evangelise - literally, ‘to give the good news’ - in order to explain who the Son of God was and what his precise message had been, and to systematise beliefs.²⁸

To put an end to the debate that so troubled the early Christian church in the west, the Emperor Constantine had called a council at Nicaea in 325, where bishops from across the empire were summoned to resolve rival interpretations about the relationship between God the Father and God the Son, one of the topics that had caused the most friction, and to resolve a host of other competing theories. The council dealt with these by agreeing a structure for the church, by settling the issue of calculating the date of Easter, and by codifying a statement of faith that still holds fast in the Christian church: the creed of Nicaea. Constantine was determined to put an end to division and to underline the importance of unity.²⁹

Bishops from Persia and elsewhere outside the boundaries of the Roman Empire had not been invited to attend Nicaea. Councils held in Persia in 410, and again in 420 and 424, were therefore organised to enable bishops to resolve the same issues that had been looked at by their peers in the west. The impulse to meet and discuss was supported by the Shah, described by one source as the ‘victorious king of kings, on whom the churches rely for peace’, who like Constantine was keen to benefit from the support of the Christian communities rather than have to intervene in their squabbles.’³⁰

The account of what was agreed at the meetings is not entirely reliable, reflecting later power struggles between leading sees and clerics. Nevertheless, important decisions clearly were made regarding the organisation of the church. It was purportedly agreed that the archbishopric of Seleucia-Ctesiphon should act as ‘head and regent over us and all our brother-bishops in the whole of the [Persian] empire’ (albeit against a backdrop of considerable argument and ill-feeling).³¹ The important question about the mechanics of how clerical appointments were made was discussed at length, with the aim of eliminating double hierarchies in locations that contained competing Christian constituencies. Thought was given to the dates of important religious festivals, while it was also determined that the common practice of appealing to ‘western bishops’ for guidance and intervention should be stopped, as this undermined the leadership of the church in the east.³² Finally, the creed and canons of the Council of Nicaea were accepted, alongside agreements that had been reached at subsequent western synods in the intervening period.³³

This should have been a seminal moment, the point where the muscle and brains of the Christian religion engaged properly, creating an institution that linked the Atlantic with the foothills of the Himalayas, with two fully functioning arms - centred on Rome and Persia, the two great empires of late antiquity - working in accord with each other. With imperial patronage in the former, and a growing acceptance by the ruler in the latter, an enviable platform had been laid that could have seen Christianity become the dominant religion not only in Europe but in Asia too. Instead, bitter infighting broke out.

Some bishops who felt undermined by the attempts to harmonise the church accused leading figures not only of not being properly educated, but of not even being properly ordained. Then there were the problems caused by an outbreak of Christian militancy, which saw a series of Zoroastrian fire temples vandalised - which in turn put the Shah in a compromising position and forced him to shift his stance away from religious tolerance towards one that championed the belief system of his aristocracy. It was a major setback. Instead of welcoming a golden age, the church found itself facing a new wave of persecution.³⁴

Fiery clerical disputes were endemic in the early church. Gregory of Nazianzus, an archbishop of Constantinople in the fourth century and one of the finest early Christian scholars, recorded being shouted down by detractors. Rivals screamed at him like a giant flock of crows, he wrote. It felt like being in the middle of a huge sandstorm when they attacked him, or being savaged by animals: ‘they were like a swarm of wasps suddenly flying in one’s face’.³⁵

Nevertheless, the timing of this particular breakdown in the middle of the fifth century was unfortunate. A bitter feud had been brewing for some time between two rival clerics in the west, Nestorius, the patriarch of Constantinople, and Cyril, the patriarch of Alexandria, over the question of the divine and human nature of Jesus. Debates like this were not necessarily settled by fair means. Cyril was a born politician, ruthless in his methods of winning support for his position, as an extensive schedule of bribes he paid out shows: influential figures, and their wives, were treated to luxury goods like fine carpets, chairs made of ivory, expensive tablecloths and cash.³⁶

Some clerics in the east found the dispute - and the nature of its resolution - bewildering. The problem, as they saw it, lay in the sloppy translation into Greek of the Syriac term describing the incarnation - although the argument was as much about jostling for power between two leading lights in the church hierarchy, and the kudos that came from having one’s doctrinal positions accepted and adopted. The clash came to a head over the status of the Virgin, who in Nestorius’ opinion should be termed not Theotokos (the one who bears God) but Christotokos (the one who bears Christ) - in other words, the human nature of Jesus alone.³⁷

Outflanked and outmanoeuvred by Cyril, Nestorius was deposed, a move that destabilised the church as bishops hastily changed their theological positions one way and then another. Decisions made at one council could be challenged at another, as rival factions lobbied fiercely in the background. Much discussion revolved around the question of whether Jesus Christ had two natures - divine and human - inviolably united in one person and how the two were linked. The precise relationship between Jesus and God was also a matter of intense debate, revolving around the issue of whether the former was the creation of the latter, and therefore subordinate, or a manifestation of the Almighty, and hence co-equal and co-eternal. Responses to the questions were set out forcefully at the Council of Chalcedon in 451, with the articulation of a new definition of faith which was supposed to be accepted throughout the Christian world - and was accompanied with the explicit threat that anyone who did not agree with it was to be expelled from the church.³⁸ The church in the east reacted furiously.

This new teaching of the western church was not just wrong, the eastern bishops argued, but verged on heresy. A reworded creed was therefore issued that set out the distinct and separate natures of Jesus, and threatened damnation for anyone who ‘considers or teaches others that suffering and change have attached to the divinity of our Lord’.³⁹ The Emperor became embroiled in the debate. He closed the school in Edessa which had become the focal point of the Christian east, pumping out texts, saints’ lives and advice not only in Syriac, the Aramaic dialect used in Edessa, but in a range of other languages too such as Persian and Sogdian.⁴⁰ Unlike in the Mediterranean, where Greek was the language of Christianity, in the east there was a recognition from the outset that if new audiences were to be attracted, there needed to be material available that could be understood by as many different groups as possible.

The closure of the Edessa school deepened the schism between the churches of the west and the east, not least because many scholars were expelled from imperial territory and sought refuge in Persia. Over time, this became increasingly problematic, as emperors based in Constantinople were expected to defend ‘orthodox’ doctrine - and to crack down on teachings deemed deviant and heretical. In 532, when a peace treaty was agreed with Persia following a period of instability and conflict in the Caucasus, one of the key clauses in the agreement was that Persian officials should help track down and take into custody bishops and priests whose views were not in line with the Council of Chalcedon and whose activities were considered dangerous by the Roman authorities.⁴¹

Trying to soothe passions between rival religious factions was a thankless task, as the case of the Emperor Justinian shows all too well. Justinian repeatedly tried to get opposing sides to reconcile their views, summoning a major Ecumenical Council in 553 in a bid to draw a line following a period of increasingly bitter recrimination, while also personally attending more low-key meetings of leading clerics to find a way towards a solution.⁴² An account written after his death shows how his efforts to find common ground were seen by some: ‘after filling absolutely everywhere with confusion and turmoil and collecting the wages for this, at the conclusion to his life, [he] passed over to the lowest places of punishment’ - that is to say, to hell.⁴³ Other emperors took a different approach and, attempting to silence the cacophony and recriminations, simply forbade discussion of religious affairs.⁴⁴

While the church in the west obsessed about rooting out variant views, the church in the east set about one of the most ambitious and far-reaching missionary programmes in history, one that in terms of scale bears comparison with later evangelism in the Americas and Africa: Christianity expanded rapidly into new regions without the iron fist of political power behind it. A rash of martyrs deep in the southern part of the Arabian peninsula shows how far the religion’s tentacles were spreading, as does the fact that the King of Yemen became Christian.⁴⁵ A Greek-speaking visitor to Sri Lanka in about 550 found a robust community of Christians, overseen by clergy appointed ‘from Persia’.⁴⁶

Christianity even reached the nomadic peoples of the steppes, much to the surprise of officials in Constantinople who, when offered hostages as part of a peace agreement, found that some had ‘the symbol of the cross tattooed in black on their foreheads’. Asked how this had happened, they replied that there had been a plague ‘and some Christians among them had suggested doing this [to bring divine protection] and from that time their country had been safe’.⁴⁷

By the middle of the sixth century there were archbishoprics deep within Asia. Cities including Basra, Mosul and Tikrit had burgeoning Christian populations. The scale of evangelism was such that Kokhe, situated close to Ctesiphon, was served by no fewer than five dependent bishoprics.⁴⁸ Cities like Merv, Gundesāpūr and even Kashgar, the oasis town that was the entry point to China, had archbishops long before Canterbury did. These were major Christian centres many centuries before the first missionaries reached Poland or Scandinavia. Samarkand and Bukhara (in modern Uzbekistan) were also home to thriving Christian communities a thousand years before Christianity was brought to the Americas.⁴⁹ Indeed, even in the Middle Ages, there were many more Christians in Asia than there were in Europe.⁵⁰ After all, Baghdad is closer to Jerusalem than to Athens, while Teheran is nearer the Holy Land than Rome, and Samarkand is closer to it than Paris and London. Christianity’s success in the east has long been forgotten.

Its expansion owed much to the tolerance and deftness of the Sasanian rulers of Persia, who were able to pursue inclusive policies at times when the aristocracy and Zoroastrian priesthood were pacified. Such was the conciliatory way that Khusraw I (531-79) dealt with foreign scholars that he became well known in contemporary Constantinople for being a ‘lover of literature and a profound student of philosophy’, something that had one writer in Constantinople spluttering in disbelief: I find it quite impossible to think, protested the historian Agathias not long afterwards, that he can really have been so brilliant. He spoke in a rough and uncivilised tongue; how could he possibly have understood the nuances of philosophy?⁵¹

By the later sixth century, meetings of the church of the east were even beginning with earnest prayers for the health of the Persian ruler. And not long afterwards the Shah could be found organising the election of a new patriarch, urging all the bishops in his realm to ‘come quickly … to elect a leader and governor … under whose administration and leadership lie every altar and every church of our Lord Jesus Christ in the empire of the Persians’.⁵² The Sasanian ruler had gone from being the persecutor of Christians in Asia to being their champion.

This was at least in part a result of a growing self-confidence in Persia, fuelled by regular payments of money by the authorities in Constantinople whose military and political priorities shifted to resolving problems elsewhere. With the steppes becalmed and Rome’s attention often focused on stabilising and recovering provinces in the Mediterranean that had fallen, the fifth and sixth centuries were a time of rising prosperity in Persia: religious tolerance went hand in glove with economic growth. Countless new cities were founded across Persia as the central government spent increasing tax revenues on infrastructure.⁵³ Massive irrigation programmes, above all in Khuzistan and Iraq, boosted agricultural production, while water-supply systems were built, or in some cases extended for several miles. An extensive bureaucratic machine ensured smooth administration from the Levant deep into Central Asia.⁵⁴This was a period that saw major centralisation of the Sasanian state.⁵⁵

The level of control went as far as setting out the layout of individual stalls in Persian markets and bazaars. One text records how trades were organised into regulated guilds, and notes that inspectors were on hand to ensure quality controls and assess the takings due to the treasury.⁵⁶ As wealth grew, so long-distance trade in luxury, high-value items rose too: thousands of seals used to mark packages as approved for sale or for export survive, as does a considerable corpus of written material attesting to contracts being sealed and kept at registry offices in this period.⁵⁷ Goods were carried from the Persian Gulf to the Caspian, and were taken to and from India by sea and by land. Levels of exchange with Sri Lanka and China rose sharply, as they also did with the eastern Mediterranean.⁵⁸ All the while, the Sasanian authorities retained a close interest in what was going on within their borders and beyond.

A considerable part of this long-range commerce was handled by Sogdian traders famous for their caravans, financial acumen and close family ties that enabled them to trade goods along the main arteries running across Central Asia into Xinjiang and western China. A remarkable cache of letters discovered by Auriel Stein in a watchtower near Dunhuang at the start of the twentieth century attest to trading patterns and sophisticated credit facilities, as well as to the goods and products that the Sogdians transported and sold. Among the many items they traded were gold and silver ornaments, such as hair clasps and finely crafted vessels, hemp, linen, woollen cloth, saffron, pepper and camphor; but they specialised in trading silk.⁵⁹ Sogdians were the glue that connected towns, oases and regions together. They played a major role in Chinese silk reaching the eastern Mediterranean, where it was highly prized by the Roman emperors and the elite. Likewise, they brought goods back in the other direction: coins minted in Constantinople have been found across Central Asia, including deep in China itself - as have prestige objects like a silver ewer depicting scenes from the Trojan War that was buried in the mid-sixth century alongside its powerful owner, Li Xian.⁶⁰

As religions came into contact with each other, they inevitably borrowed from each other. Although it is difficult to trace this accurately, it is striking that the halo became a common visual symbol across Hindu, Buddhist, Zoroastrian and Christian art, as a link between the earthly and the divine, and as a marker of radiance and illumination that was important in all these faiths. A magnificent monument at Tāq-i Bustān in modern Iran depicts one ruler on horseback, surrounded by winged angels and with a ring of light around his head in a scene that would have been recognisable to followers of any of the great faiths of this region. Likewise, even poses - like the Buddhist vitarka mudra, formed from the right thumb and index finger of one hand touching, often with the other fingers outstretched - were adopted to illustrate connections with the divine, favoured particularly by Christian artists.⁶¹

Christianity flowed along trade routes, but its progress did not go unchallenged. The centre of the world had always been noisy, a place where faiths, ideas and religions borrowed from one another - but they also clashed. Competition for spiritual authority became increasingly intense. Such tension had long marked the relationship between Christianity and Judaism, where religious leaders on both sides strove to draw lines between the two: in the case of the former, intermarriage was repeatedly legislated against, while the date of Easter was deliberately moved so as not to coincide with the feast of Passover.⁶² This was not far enough for some. John Chrysostom, archbishop of Constantinople at the turn of the fourth century, urged that the liturgy should be more exciting, complaining that it was difficult for Christians to compete with the theatricality of the synagogue where drums, lyres, harps and other musical instruments made for entertainment during worship - as did actors and dancers brought in to enliven proceedings.⁶³

Senior Jewish figures, for their part, were no more enthusiastic about receiving new converts. ‘Do not have faith in a proselyte,’ declared one famous rabbi, iyya the Great, ‘until twenty-four generations have passed because the inherent evil is still within him.’ Converts are as irritating and difficult as scabs, noted elbo, another influential rabbi.⁶⁴ Jewish attitudes to Christianity hardened in Persia as a result of the inroads being made by the latter. This can be seen clearly from the Babylonian Talmud, the collection of texts centred on the rabbinic interpretation of Jewish law. Unlike the Palestinian Talmud, which refers to Jesus lightly and in passing, the Babylonian edition takes a violent and scathing position on Christianity, attacking doctrines, specific events and figures from the Gospels. The Virgin birth, for example, is lampooned and mocked as being as likely as a mule having offspring, while the story of the Resurrection is mercilessly ridiculed. Detailed and sophisticated counter-narratives of Jesus’ life, including parodies of scenes from the New Testament and above all from the Gospel of St John, show how threatening Christian advances had become. There was a systematic effort to assert that Jesus was a false prophet, and that his crucifixion was justifiable - in other words, deflecting blame and responsibility away from the Jews. These violent reactions were an attempt to counter the steady gains that were being made at Judaism’s expense.⁶⁵

It was important, therefore, that there were also locations where Judaism itself made progress. In the kingdom of imyar in the south-western corner of the Arabian peninsula, in what is now Saudi Arabia and Yemen, Jewish communities became increasingly prominent, as recent discoveries of synagogues such as the fourth-century structure at Qana shows.⁶⁶ Indeed, imyar adopted Judaism as the state religion - and did so enthusiastically. By the late fifth century, Christians were being regularly martyred for their beliefs, including priests, monks and bishops, after being condemned by a council of rabbis.⁶⁷

A botched Ethiopian military expedition across the Red Sea in the early sixth century to replace the Jewish ruler with a Christian puppet resulted in vicious reprisals as steps were taken to remove all traces of Christianity from the kingdom. Churches were demolished or turned into synagogues. Hundreds of Christians were detained and executed; on one occasion, 200 who had taken sanctuary inside a church were simply burnt alive. All this was reported with glee by the king, who sent letters across Arabia rejoicing at the suffering he had inflicted.⁶⁸

The Zoroastrian priesthood also reacted to Christianity’s progress in the Sasanian Empire, especially following several high-profile conversions of members of the ruling elite. This too resulted in a series of aggressive attacks on Christian communities, including multiple martyrdoms.⁶⁹ In turn, Christians began to produce uncompromising morality tales, the most famous of which was the epic story of Qardagh, a brilliant young man who hunted like a Persian king and argued like a Greek philosopher but gave up a promising career as a provincial governor to convert. Sentenced to death, he escaped from captivity only to experience a dream telling him it was better to die for his faith than to fight. His execution, at which his father threw the first stone, was commemorated in a lengthy and beautiful narrative account whose aim was evidently to encourage others to find the confidence to become Christian.⁷⁰

Part of the secret of Christianity’s success lay in the commitment and energy of its evangelical mission. It helped, of course, that the enthusiasm was infused with a healthy dose of realism: texts from the early seventh century record clerics working hard to reconcile their ideas with those of Buddhism, if not as a short cut, then at least as a way of simplifying matters. The Holy Spirit, wrote one missionary who reached China, was entirely consistent with what the local population already believed: ‘All buddhas flow and flux by virtue of this very wind [that is, the Holy Spirit], while in this world, there is no place where the wind does not reach.’ Likewise, he went on, God has been responsible for immortality and everlasting happiness since the creation of the world. As such, ‘man … will always do honour to the name of Buddha’.⁷¹ Christianity was not just compatible with Buddhism, he was saying; broadly speaking, it was Buddhism.

Others tried to codify the fusion of Christian and Buddhist ideas, producing a hybrid set of ‘gospels’ that effectively simplified the complex message and story of the former, with elements that were familiar and accessible to populations in the east in order to accelerate Christianity’s progress across Asia. There was a theological logic to this dualistic approach, usually called Gnosticism, which argued that preaching in terms that had understandable cultural reference points and used accessible language was an obvious way to spread the message.⁷² Little wonder, then, that Christianity found support among a broad sweep of the population: these were ideas that were deliberately made to sound familiar and easy to grasp.

Other cults, faiths and sects benefited from the same process. The teachings of Mazdak, a charismatic preacher, proved extremely popular in the late fifth and early sixth century - as we can tell from the furious and colourful criticism showered on the preacher’s followers by Christian and Zoroastrian commentators alike. The attitudes and practices of Mazdak’s disciples, ranging from what they ate to their supposed interest in having group sex, were electrifyingly vilified. In fact, in so far as the highly partial source material allows us to understand, Mazdak advocated an ascetic lifestyle that had obvious resonances with Buddhist attitudes to material wealth, to Zoroastrian suspicions of the physical world and to well-established Christian asceticism.⁷³

In this competitive spiritual environment, it was important to defend intellectual - and physical - territory. A Chinese traveller passing through Samarkand in the sixth century noted that the local population violently opposed the law of Buddha, and chased away with ‘burning fire’ any Buddhist who tried to take shelter.⁷⁴ On this occasion, the hostile reception had a happy ending: the visitor was eventually allowed to convene a meeting and apparently went on to persuade many to convert to Buddhism thanks to the strength of his character and of his arguments.⁷⁵

Few understood better than the Buddhists how important it was to publicise and show off objects that supported declarations of faith. Another Chinese pilgrim who made his way to Central Asia in search of Sanskrit texts to study looked with wonder at the sacred relics venerated by the local population in Balkh. These included one of the Buddha’s teeth, as well as the basin he used for washing, and a brush he used for sweeping, made of the kasha plant, but decorated with fine jewels.⁷⁶

There were, however, more visible and more dramatic statements that were designed to win hearts and minds. Cave temples had become a well-established way of evoking and enforcing a spiritual message, lying along trade routes and eliding the idea of sanctuary and the divine on the one hand with commerce and travel on the other. The complex at Elephanta off the coast of Mumbai and the Maratha caves at Ellora in northern India provide spectacular examples. Filled with majestic and ornate carvings of deities, these were designed to showcase moral and theological superiority - in this case, the superiority of Hinduism.⁷⁷

This had an obvious parallel with Bamiyan (in modern Afghanistan). Lying at the crossroads of routes linking India to the south, Bactria to the north and Persia to the west, Bamiyan contained a complex of 751 caves supplemented by immense figures of the Buddha.⁷⁸ Two statues, one to a height of 180 feet and another, slightly older, approximately two-thirds of the size, stood carved into vast niches in the rocks for nearly 1,500 years - until they were blown up and destroyed by the Taliban in 2001 in an act of philistinism and cultural savagery that stands comparison with the destruction of religious artefacts in Britain and northern Europe during the Reformation.⁷⁹

When we think of the Silk Roads, it is tempting to think of the circulation always passing from east to west. In fact, there was considerable interest and exchange passing in the other direction, as an admiring seventh-century Chinese text makes plain. Syria, the author wrote, was a place that ‘produces fire-proof cloth, life-restoring incense, bright moon-pearls, and night-lustre gems. Brigands and robbers are unknown, but the people enjoy happiness and peace. None but illustrious laws prevail; none but the virtuous are raised to sovereign power. The land is broad and ample, and its literary productions are perspicuous and clear.’⁸⁰

And in fact, despite fierce competition and in spite of the chorus of religions fighting to make their voices heard, it was Christianity that kept chipping away at traditional beliefs, practices and value systems. In 635, missionaries in China were able to convince the Emperor to withdraw opposition to the faith and to recognise it as a legitimate religion whose message not only did not compromise imperial identity but potentially enforced it.⁸¹

Around the middle of the seventh century, the future seemed easy to read. Christianity was on the march across Asia, making inroads at the expense of Zoroastrianism, Judaism and Buddhism.⁸² Religions had always played off each other in this region, and learnt that they had to compete for attention. The most competitive and successful, however, turned out to be a religion born in the little town of Bethlehem.⁸³ Given the progress that had been made over the centuries that followed the crucifixion of Jesus at the hands of Pontius Pilate, it should have been only a matter of time before the tentacles of Christianity reached the Pacific, linking the great ocean with the Atlantic in the west.

And yet, at the moment of the triumph of Christianity, chance intervened. A platform had been laid for a spiritual conquest that would not just connect towns and regions, but span continents. At that moment, however, a debilitating war broke out which undermined the existing powers and opened up opportunities to new entrants. It was like unleashing the internet in late antiquity: suddenly, a new raft of ideas, theories and trends threatened to undermine the existing order, and to take advantage of the networks that had been established over centuries. The name of the new cosmology did not reflect how revolutionary it was. Closely related to the words for safety and peace, ‘Islam’ gave little sense of how the world was about to change. Revolution had arrived.