ABSTRACT
In the course of the first 'Abbasid century (750-850) in the world of Islam, Constantinople and Jerusalem lost the seemingly free and easy colloquy they had enjoyed for more than a century across the borders of the Roman empire and the newly established caliphate of the Muslim Arabs. Indeed for a time, to judge by the relationships between the Christian churches in the seventh and eighth centuries, it had been almost as if the frontier between two rival political monotheisms did not exist. Although Islam had monumentally stated its objection to Christianity in the very heart of Jerusalem with the construction of the Dome of the Rock in the reign of the caliph 'Abd al-Malik (685-705), and every year the caliph's forces tried again to capture Constantinople, in the eighth century Christians living in the Holy City continued to make substantial contributions to the life of the Greekspeaking church of Byzantium. In fact, as Cyril Mango has written, 'the most active centre of Greek culture in the eighth century lay in Palestine, notably in Jerusalem and the neighbouring monasteries' .1 Constantinople and Jerusalem were still just over one another's horizons.2
