Jews were settled in medieval western Christendom prior to the year 1000, although in relatively small numbers. Those early Jews left almost no evidence of their existence to posterity. They seem to have exerted little impact on the larger number of Jews who came to populate a rapidly changing western Christendom subsequent to the year 1000. We find very few references in that later period to precedents from earlier Jewish life in Europe.

This is not to say that, as Jewish numbers expanded in medieval western Christendom, these later Jews and their Christian neighbors were unaffected by pre-existent legacies and innovated freely with respect to Jewish circumstances. To the contrary, Jewish life, as it expanded all across medieval western Christendom from south to north, was deeply affected by inherited structures and attitudes. By the year 1000, Jews across the globe had evolved a rich social and intellectual framework for living as a creative minority within monotheistic majority societies. At the same time, the Christian majority was heir to a set of complex and ambivalent policies toward and perceptions of Judaism and the Jews. Surprisingly, perhaps, we must begin with the prior legacy of Islam and its stances toward Jews living under its rule. Since so many of the Jews who were absorbed into medieval western Christendom after the year 1000 came – involuntarily (through Christian conquest) or voluntarily (through immigration) – from the Muslim sphere, their circumstances and expectations played a significant role in the Jewish experience in medieval western Christendom.