Syriac Christian legal responses to Islam changed significantly over the first two hundred years of Muslim rule. In this paper, I will focus first on how Christian leaders responded to Christians who converted to Islam, then sought to return to Christianity, and second, how these leaders categorized Muslims from a legal perspective. Converts from Islam to Christianity emerge as early as the late seventh century C.E. Christian leaders responded to these cases in a variety of ways. A trend from leniency to strictness emerges over the course of the seventh, eighth, and ninth centuries, as conversion to Islam became more common and more devastating to Syriac Christian communities. Jacob of Edessa (d. 708 C.E.) was a prominent example of this early leniency toward Christians who converted Islam. He allowed deathbed conversions from Islam to Christianity and permitted those who did so to receive communion. Those who recovered from illness were required to do penance for having converted to Islam, but after completion of their penance were again allowed to receive communion. By the ninth century C.E., in contrast, converts to Christianity from Islam were required to reject Muhammad by name, along with the Qur’an, various Islamic teachings, the family and associates of the Prophet, and even Mecca and the ‘God of Muhammad.’ Adults who had chosen to convert away and revert back were let into the church, but were not allowed to receive communion again until the end of their lives. Syriac Christians referred to Muslims by a variety of terms in the seventh century (hanpe, mhaggre, tayyaye, etc.) but the term hanpe is particularly common in legal writing. The use of hanpe to describe Muslims continued in Syriac legal texts into the eighth century, even once other Syriac terms referring to Muslims became more common in other genres. I argue continued use of the term hanpe in legal contexts to refer to Muslims designated a legal status for Muslims as a religious ‘other’ – a status that defined and controlled how Syriac Christians could interact with hanpe (including both pagans and Muslims), what was required of people converting to Syriac Christianity from Islam or paganism, and other regulations.