Merchants were not the only people to cross the divide. Edessa was one of the great Byzantine university towns, and the scholars it attracted from Persia and beyond led to a rich cross-fertilisation of ideas in its lecture halls. There was a marked influence of Persian and Indian ideas on Edessa’s theology, and its theological school became notorious for the dangerous heterodoxy of its teachings. In this cosmopolitan environment the city’s most notorious heretic, Bardaisan of Edessa, was able to write an accurate account of the dietary regimes of Hindu priests and Buddhist monks, while Indian stories and legends came to be written down in unexpected new Christian incarnations: it may have been through Edessa that the Life of the Buddha passed into Byzantine (and ultimately Western) monastic libraries.
It was not a one-way traffic. There was a School of the Persians in Edessa, and in the sixth century no fewer than three Patriarchs of the Persian-based Nestorian Church were recorded as having spent much of their youth in Edessa studying Greek medicine and philosophy. Built as it was on the philosophical faultline that ran between the Eastern and Western worlds, Edessa became a great crucible fizzing with strange heresies and exotic Gnostic doctrines. One sect, the Elchasiates, believed that two gigantic angels had appeared to their founder, Elchasaios, and told him that Christ was reincarnated century after century, and that each time he was born of a virgin. The angels also instructed Elchasaios that his followers should venerate water as the source of life, and passed on a mystic formula to be used whenever members of the cult were bitten by a mad dog or a snake. To add to the richness of the mix, the Elchasiates observed the ancient Jewish Mosaic laws, circumcising their male children and scrupulously keeping the Sabbath, as well as holding out against new-fangled innovations to the New Testament such as the Letters of St Paul.
More unorthodox still were the Marcionites, who took a rather different attitude to Judaism: they believed that the stern Jehovah of the Old Testament was different from – and indeed was the enemy of – the true, kind, creator-God of the New Testament. If this was so, then, logically, the heroes of the Old Testament were actually villains: all over Edessa Marcionite churches rang with praise of Cain, the Sodomites, Nebuchadnezzar and, above all, the Serpent of the Garden of Eden.
In contrast, the Messalians, bitter enemies of the Marcionites, looked on the Cross as the object of their loathing, and refused to revere Mary as the mother of God. They strongly believed that it was possible to exorcise demons through prayer: if you prayed hard enough, they maintained, the demon would exit from the nose as mucus, or from the mouth as saliva. Once this had happened and the believer had achieved union with the Holy Spirit, he could henceforth do whatever he liked: no amount of sin and debauchery could harm his soul, as it was already part of God. A breakaway group from the Marcionites, the Carpocratians, took this view to an extreme: they maintained that to achieve true freedom the believer must scrupulously ignore the distinction between what is good and what is evil.
Straitlaced clerical visitors to Edessa were horrified to discover that Orthodoxy – true Christianity as understood elsewhere in the Christian world – was regarded by many in Edessa as only one among a considerable number of options available to the inquiring believer, and that the teachings of all these different sects tended to be regarded as equally valid. As in the very early Church of the first century, doctrine was still in a state of continual flux, and no one interpretation of the Christian message and no single set of gospels had yet achieved dominance over any others. Indeed in Edessa in the sixth century the Orthodox were known merely as Palutians, after a beleaguered former bishop of the town. Visitors were appalled: if it were possible to understand Christianity in so many radically different ways in one town, what would happen if these heretical tendencies were to spread across the Empire?
Strange things certainly went on in Edessa. In 578, the year in which John Moschos set off on his travels, a group of prominent Edessans – including the provincial governor – were caught red-handed performing a sacrifice to Zeus. Even worse, many Edessans openly professed themselves Manicheans, members of a cult so weird and inventive – even by local standards – that it was unclear whether Manicheans were heretical Christians, heretical Zoroastrians, Pagan survivals or a completely new religion altogether.
In Edessa it seems that any belief or combination of beliefs was possible – as long as it was inventive, unorthodox, deeply weird and extremely complicated. But what such a flourishing proliferation of different faiths highlights is the fact that it was only by a series of historical accidents – or, if you like, the action of the Holy Spirit – that the broad outlines of our own understanding of Christianity came to be seen as accepted and established, and that Manichean, Marcionite and Gnostic ideas came to be deemed heretical. After all, a theologian as intelligent as St Augustine of Hippo could spend several years as a champion of Manicheism before being won over to what we now regard as more acceptable beliefs. In the uncertain world of early Christianity it does not seem impossible that the Manichees or the Gnostics could have won the day, so that on Sundays we would now read the Gospel of Philip (which emphasises Jesus’s lustily red-blooded attachment to Mary Magdalene) and applaud the Serpent of the Garden of Eden. Churches would be dedicated not to ‘heretics’ like St John Chrysostom but rather to Manichean godlings such as the Great Nous and the Primal Man; reincarnation would be accepted without a second thought, and Messalian mucus-exorcisms would take place every Sunday after evensong.
For months before I set off on this journey, while waiting for my wife to recover from a burst appendix and the succession of operations which followed it, I sat by her hospital bed reading about the bizarre percolation of heresies that once flourished in the Edessan bazaars. But it was only this afternoon, coming out of the bazaar and stumbling by accident across the old Edessa museum, that I was actually able to picture the milieu in which this whirligig of strange theologies could flourish. For there in the garden of the museum lay the finely-carved stone images of late antique Edessans who may once have subscribed to some of the heresies that circulated so promiscuously in the city between the first and seventh centuries A.D.
On the left as you entered the sculpture garden stood a figure dressed like a Roman senator, complete but for his missing head. It was an Imperial Roman sculpture the double of which you might expect to see in any archaeological museum from Newcastle to Tunis, from Pergamum to Cologne. Classical superciliousness was expressed in every inch of the man’s bearing: one arm hung loose, the other was hitched up to his breast by the fold of his toga; one leg was pushed slightly forward, the shoulders were pulled slightly back. The robes fell easily over a slight but firm physique. The head may have been missing, but the figure’s bearing still managed to give the impression of effortless Imperial superiority, the same pose that was adopted by the late Victorians to portray their empire-builders (and whose statues, sometimes similarly headless, now lie tucked into similar corners of museums across India). Who was this toga-wearing plutocrat? A governor posted to the East from his home in Alexandria, Antioch or Byzantium? Some Imperial functionary’s ambitious nephew or promising younger son, sent briefly to the Persian frontier before being promoted to a senior position at the Imperial court?
Three feet to the right of the Roman, but representing a world many thousands of miles to the East, stood another male figure, this time in the dress of a Parthian noble: the long flowing shirt and baggy pantaloons, drawn in tight at the ankle, that are still worn with little alteration as the salvar kemise of modern Pakistan. Unlike the Roman, this Edessan nobleman was thickly bearded and his hair piled high over his head in a topknot. A sword lay buckled at his waist and he wore a pair of Central Asian ankle boots. The same figure could be seen in a hundred Kushan sculptures across northern India, Afghanistan and Iran; he stood here between the Tigris and the Euphrates, but he would have been equally at home beside the Oxus, or even further to the east, the Yamuna.
Near this Parthian warrior stood a third figure, who represents the typically Edessan synthesis of both the other sculptures. He was also wearing Parthian dress, but his face and hairstyle were Roman: cropped short, with a tightly clipped beard; moreover he did not wear Parthian boots but a pair of Roman sandals. He appeared lost in thought, and held not a sword but a book. He looked bourgeois, educated and highly literate, cross-cultural and probably multilingual. Here then was exactly the sort of character who could have fitted happily into one