Roman Toletum became the capital of Visigothic Spain in the sixth century, and the church councils held here — the third, in 589, at which King Reccared abandoned Arianism for Catholicism — made the city the ecclesiastical head of the peninsula. Its archbishop is still titled Primate of Spain. Muslim armies took the city in 711 or 712, and for nearly four centuries it was Ṭulayṭulah, capital of the Middle March of al-Andalus, chronically rebellious against Córdoba and, after the caliphate broke apart in 1031, an independent taifa under the Banū Dhī l-Nūn.
Alfonso VI of León-Castile took Toledo in 1085 — the largest prize of the early Reconquista, and the event that pushed the Castilian frontier south past the Tagus. The surrender terms let Muslims and Jews stay, and they did. What followed is the reason to come: three religious communities living in one walled city for four hundred years, building for each other. Muslim craftsmen raised synagogues for Jewish patrons under Christian kings, and the resulting Mudéjar style — brick, horseshoe arches, carved plaster, coffered wooden ceilings — is the physical signature of the whole city.
Toledo was also where Arabic and Hebrew learning entered Latin Europe. From the twelfth century, under Archbishop Raymond and later under Alfonso X (r. 1252–84), scholars working in the city translated Ptolemy’s Almagest, Aristotle with his Arabic commentators, Euclid, Avicenna and al-Khwārizmī out of Arabic and Hebrew into Latin and then into Castilian. Gerard of Cremona came from Italy for the Almagest and stayed for decades. Historians argue about whether the “School of Translators” was ever a school; nobody argues about the output.
The convivencia ended badly. The Jewish quarter was sacked in 1355 and again in the pogroms of 1391, and the Alhambra Decree of 31 March 1492 expelled Spain’s Jews outright; of ten or more synagogues, two survive as monuments. Philip II moved the court to Madrid in 1561 and Toledo stopped growing, which is why so much of the medieval city is still standing. Its steel trade outlived everything: blades have been made here since Roman times, and a few working forges remain.