Jews lived in Iberia from Roman times, but Sepharad flowered under Muslim al-Andalus, where Arabic learning and courtly patronage produced a golden age: Hasdai ibn Shaprut serving the Cordoban caliphs, Samuel ha-Nagid commanding armies for Granada, the poetry of Judah Halevi and Solomon ibn Gabirol, and the towering figure of Maimonides, born in Cordoba in 1138, whose legal code and Guide of the Perplexed shaped all later Judaism. The documents of the Cairo Geniza, studied exhaustively by S. D. Goitein, show this Mediterranean Jewish world as one connected society of merchants, scholars and families from Spain to Egypt and beyond.
Christian reconquest changed the terms slowly, then catastrophically. The massacres of 1391 drove thousands into baptism, creating the conversos whose secret loyalties the Spanish Inquisition was founded to hunt. In March 1492, fresh from conquering Granada, Ferdinand and Isabella signed the Alhambra Decree expelling every professing Jew from Spain; Portugal followed in 1497 with forced conversion rather than exile.
The exiles rebuilt in the lands that would take them. The Ottoman sultans welcomed them into Istanbul, Izmir and above all Salonica, which became a majority Jewish city for four centuries. Others settled Morocco and North Africa, Italy, and eventually Amsterdam, whose Portuguese former conversos returned openly to Judaism and founded the first Jewish communities of the New World.