of doctrine; at that point Muslims rose to rebut the Jews’ fabrications and the doubts they stirred, examining their doctrines with a method grounded in reason and evidence.

As for the Christians, controversy between them and the Muslims began in Abyssinia during the first migration. The discussion turned on the reality of Christ, the divine Word, and other issues related to the Islamic creed concerning him. Later a delegation of Christians from Najran came to Madinah and debated the Prophet—may Allah bless him and grant him peace—about Jesus, peace be upon him; the Prophet then invited them to the mubahala (mutual imprecation). Allah the Exalted says: “If anyone disputes with you concerning him after the knowledge that has come to you, say: ‘Come, let us call our sons and your sons, our women and your women, ourselves and yourselves; then let us pray earnestly and invoke the curse of Allah upon the liars’” (Q 3:61).

When Islam subsequently reached Syria, Iraq, and Egypt, Christianity entered into a fierce intellectual contest with it. Debate flared over the nature of Christ, questions of divinity, the concepts of substance and accident, the Trinity and divine unity, and the doctrines of original sin and the crucifixion. The polemics reached their height after John of Damascus—the Umayyad court physician who had laid down for the Christians the rules of disputing with Muslims—through another Christian, the Egyptian John of Nikiu, who travelled to Abyssinia and began sending letters to the Copts of Egypt during the Abbasid period, attempting in them to critique Islamic beliefs and prevent their acceptance of Islam. (1)