This was a period of tremendous change in the region.
Within a hundred years after the Prophet Muhammad’s death (June 632), Muslim armies had driven the Christian Byzantine rulers out of the eastern Mediterranean, destroyed the Persian Sassanid Empire (651), conquered North Africa and were poised to attack Spain. The Christian Patriarchates of Jerusalem, Antioch and Alexandria in Egypt were under Muslim control, as were about half of the world’s Christians.
We are dealing here with a period of five centuries corresponding to: the Umayyad Caliphate (661-750) and the Abbasid Caliphate (750-1158).
So, what happened?
After disagreement and bloodshed among Muslims over who was to succeed the Prophet Muhammad, the Umayya family of Mecca was victorious. This began the Umayyad Caliphate, centered in Damascus. The Umayyads found themselves the unprepared rulers over a large, very developed and sophisticated part of the Middle East — and the overwhelming majority of their subjects were Christians. However, these Christians were often bitterly divided among themselves between those who followed the teachings of the Council of Chalcedon (451) and who formed the Church of the Byzantine Empire, and those who did not — primarily the Church of the East and the Monophysites Churches. Often this latter group found its situation better under Muslim overlords than under Byzantine Christians who considered them schismatic at best. In addition, Muslims at times actively discouraged Christians from converting to Islam.
The Umayyad Caliphate needed administrators and trained bureaucrats — and Christians fit the bill. Thus we find the grandfather and father of St. John Damascene (676-749) working at the Umayyad Court. Although they were dhimmy — i.e. protected but second class citizens — Christians played an important role in the caliphate as administrators and scholars. Christians, like John Damascene, were not sure what to make of Islam. John, for example, thought that it was a Christian heresy, having as it does so much in common with Christianity. As time went on, Christians realized that Islam was, in fact, another religion rooted in the Quran; Christians began to respond accordingly. Nonetheless, relations between the Christians and Muslims in the Umayyad Caliphate were generally not hostile.
The Umayyad Caliphate came to a violent end with the Abbasid revolt of 750. Many in the ruling Umayyad family were killed and a new caliphate set up in the new city of Baghdad.
Although Christians often rose to high positions in the government, and made up a majority, the Abbasids were not nearly as dependent on them for the administration of the caliphate. The Church of the East moved its Patriarchal See from Ctesiphon, the former Persian capital, to Baghdad, the new Abbasid capital.
This was a time of great intellectual activity and Christians played a major role. Syriac-speaking monks of the Church of the East had kept alive the traditions of the Greek philosophers such as Aristotle. The emerging Muslim intellectual class with its philosophers and theologians interacted with Christian scholars. Timothy I, Patriarch-Catholicos of the Church of the East, was a prominent scholar of Aristotle. (Caliph al-Mahdi even hired Timothy to translate Aristotle’s work The Topics for the caliph’s library.)
During this time, Muslims and Christians engaged in dialogues/debates on the respective strengths of their religions — and often these encounters were sponsored by the caliphs themselves. Texts of many of these debates still exist today — and you can see some important developments.
With time, the Christian critiques of Islam began to get harsher. One also gets the distinct feeling that these texts were directed more to Christians than Muslims. This indicates that by the end of the 8th century, Christians —for any number of reasons, force not being among them — were beginning to convert to Islam.
As the Abbasid Caliphate went into a long, slow decline, missionaries of the Church of the East remained active throughout Asia. Christianity was learning to express its faith using Arabic, the language of the Quran. It was a time of Christian-Muslim interaction, if not dialogue. Although Christians were not persecuted, one begins to note increasing social, cultural and financial motivations for Christians to convert to Islam.
But other forces were at work.After the Abbasids, Mongol invaders launched more than a century of widespread destruction that overwhelmed the Middle East, indirectly contributing to what became a centuries-long decline of Christianity in the region.
Related:
2,000 Years of Christianity in Syria and Mesopotamia — Part 1: In the Beginning
2,000 Years of Christianity in Syria and Mesopotamia: Introduction