This article records tradition as it has been passed down and reported. Its sources are not yet part of the atlas's verified catalogue.
The Alhambra Decree of 1492, issued by the Catholic Monarchs Ferdinand and Isabella, ordered the Jews of Castile and Aragon to convert to Catholicism or leave their kingdoms outright. Those who stayed and accepted conversion became conversos, a community whose sincerity the Spanish Inquisition would go on to police for generations afterward, treating baptism as a beginning rather than a settled answer.
Those who chose instead to continue practising Judaism openly were expelled, somewhere between one hundred thousand and two hundred thousand people by the source's own uncertain range, since exact figures for an expulsion carried out across a single kingdom in a single year were never reliably recorded. Their departure ended seven centuries of organised Jewish life on the Iberian Peninsula, scattering its communities across North Africa, the Ottoman Empire and the rest of Europe.
What this changed for Judaism's spread was the sudden closing of seven centuries of organised Jewish life on the Iberian Peninsula, and the opening of new centers wherever the expelled communities resettled. The choice the Alhambra Decree forced, conversion or departure, split a single Iberian Jewish community into conversos who remained under Inquisition scrutiny and exiles who carried Sephardic Judaism outward across North Africa, the Ottoman Empire and the rest of Europe.