Dating coptic crosses
Though the Abbasids showed tolerance towards the other religious, non-Muslim groups, still their tolerance was displayed mostly vis-a-vis some of their coreligionists who lived on the margins of traditional Islam.The Christians, especially the Melkites who lived in the eastern provinces of the empire, had much to endure.There were also other opponents who questioned the legitimacy of the Abbasids' claim to the caliphate.As for the Christians as well as for the rest of ahl-al-Dhimmi, the Abbasid era would prove to be less tolerant of non-Muslims and would either re-enact old anti- Christian legislation or create new restrictions.
Christians and Jews were enjoined to affix wooden images of devils to their houses, level their graves even with the ground, wear outer garments of yellow colour, and ride only on mules and asses with wooden saddles marked by two pomegranates-like balls on the cantle.
Before, al-Mutawakkil Abu Gafar al-Mansur (754-775) imposed many vexing measures upon the Christians.
In 756, he forbade Christians to build new churches, to display the cross in public, or to speak about religions with Muslims.
In Baghdad itself, there were apparently many important monasteries, groups of professors, and students.
There were, for example, the school of Deir Kalilisu and Deir Mar Fatyun and the school of Karh.