From The Holy Mountain by William Dalrymple Page B

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 nourished 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