Under the general rubric of ‘Abrahamic Religions’ there is a sub-topic that highlights particular similarities between Islam and Christianity in areas of institutional and societal development. As joint inheritors of a Judaic theological and ethical legacy and a Hellenistic philosophical and scientific legacy, Islam and Christianity ‘co-evolved’ in directions that did not have distinct parallels in Judaism, which remained particularistic rather than universal in nature. Among the areas in which the two faith traditions converged were sin and salvation, spirituality and mysticism, conversion, state and law, violence and toleration, word and language, clergy, and education and mission. The degree of convergence warrants the assigning of the label ‘Islamo-Christian Civilization’ to the partially shared—though also antagonistic—social, institutional, and political structures that emerged over a period of fourteen centuries.
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).