On march 30, 1492, Spain committed one of those acts of great self destructive folly to which superpowers are prone: it expelled its Jews. For centuries, the Jews had been a rich and thriving presence in Iberia. Not incidentally, they were also a great economic benefit to their Moslem and, later, Catholic hosts. To be sure, the land they knew as Sepharad was no utopia for the children of Israel. They suffered harassment, slander, and, on occasion, physical attack. And the Catholic Church took a particularly keen interest when Jews were accused of encouraging conversos – onetime Jews who had converted to Christianity – to return to Judaism. Moreover, Jewish political and legal rights had always been severely circumscribed. But the Jews of Spain nonetheless enjoyed favor at a high level. Though some of the monarchs who protected them may have been moved by humanitarian feelings, most were thinking mainly of their own political and material self-interest. The king of Aragon, for one, recognized the practical benefits of having an economically active Jewish community within his realm. They were skilled merchants, and they controlled a far-flung commercial network. Up to the end of the fourteenth century, the Jews were able to carry on in their communities with a tolerable amount of peace and security. Some of the scholars among them even occupied posts at the royal courts.

All of this changed in 1391. Beginning in Castile, the largest kingdom in medieval Spain, unruly crowds – usually from the lower classes and incited by demagogic preachers – began burning synagogues or converting them into churches.