A century after its birth in the western Arabian Peninsula at the beginning of the seventh century, Islam had conquered the Middle East, Africa, and part of Southern Europe. This vibrant, expanding religion had established its western outpost in what is today most of Spain and Portugal.

What followed may be surprising to those familiar with the history of medieval religious polities on both sides of the Mediterranean. Here more than elsewhere in the Muslim world — not to mention the Christian states of Europe — minority faiths enjoyed a degree of toleration. Christians and Jews were able, at least during certain times, to continue to practice their faith, sometimes even alongside Muslims.

The Koran advocated acceptance of what Mohammed called other “religions of the Book,” such as Christianity and Judaism. However, such acceptance was generally accompanied, in practice, by certain forms of discrimination against the followers of these faiths — notably the requirement to pay additional taxes.