How does Christianity explain the existence of the two rival Abrahamic faiths, Judaism and Islam? What place does it allow in Christian society for Jews and Muslims? The responses to these questions are many; this chapter examines a few prominent examples. Rather than a survey of Christians’ attitudes towards Jews (or Judaism) and Muslims (or Islam), it examines how Christian law accommodated Jews and Muslims as residents of Christian societies and at the roles that Christian thinkers assigned to Judaism and Islam in a Christian scheme of history. The emphasis is on a few salient examples from the fourth century (when Christianity obtains social and intellectual predominance in the Roman Empire) to the nineteenth (when Christianity loses that predominance in Europe).