Theodore Abū Qurrah was one of the well-known figures of the Christian Arab writers in the late eighth and early Ninth centuries. He was a bishop of the city of Ḥarrān, and was somehow related to the Monastery of Saint Saba in Jerusalem. He was also one of the few Arab Melkite Christians who were supposedly still mastering the Greek language and had more or less some ties with the Byzantine church and theology. His debate at the court of the Abbasid Caliph al-Ma'mūn(813-833 A.D./189-218 A.H.) is one of the earliest recorded religious debates between Christianity and Islam. Of this debate there are several and various surviving manuscripts; they amount to more than 30 different copies scattered between Europe and some private libraries in Syria. These copies of one single debate attracted several scholars, among them G. Graf, who undermined the authenticity of the debate. Meanwhile, other scholars such as I. Dick and A. Guillaume defended the genuineness of the text. At the same time, both sides admitted the striking differences between all the copies.  One of the earliest copies of this debate has recently been the subject of a detailed discussion by David Bertaina in his Ph.D. thesis which is entitled: An Arabic Account of Theodore Abū Qurrah in Debate at the Court of Caliph al-Ma'mūn: a Study in Early Christian and Muslim Literary Dialogues. In his thesis Bertaina published, translated, and commented on a manuscript of the dialogue attributed to Theodore Abū Qurrah at the court of the caliph al-Ma'mūn.