Cordoba

Abd al-Rahman I began the congregational mosque of Cordoba in 785, on ground that had held a Visigothic church; later Muslim writers say the site was first shared and then bought outright, an account that comes from centuries afterwards and cannot be checked. The builders reused Roman and Visigothic columns, which came in different heights, and solved the problem by stacking two tiers of arches in alternating brick and stone, producing the forest of red and white horseshoes that the building is known for. Three later rulers extended it, and al-Hakam II added a prayer niche whose gold ground mosaics were made by craftsmen sent, according to the chronicles, by the Byzantine emperor.

The caliphate declared at Cordoba in 929 gave al-Andalus a ruler claiming the title in his own right, in competition with Baghdad and with the Fatimids, and the mosque was the architectural statement of that claim.

Ferdinand III took the city in 1236 and the mosque became a cathedral, which is why it survived when so much else did not. In the 1520s the chapter cut a Renaissance nave and choir through the middle of the hall, over the objection of the city council; the emperor Charles V, who had approved the work, is reported to have said on seeing it that they had built what could be built anywhere and destroyed what was unique in the world. The building is a working cathedral today, and Muslim requests to be allowed to pray in it, along with arguments about what it should be called, have been refused and remain live.

Two men born in Cordoba twelve years apart went on to shape philosophy in three religions, and both careers were determined by the same event. The Almohads took the city in the middle of the twelfth century and ended the arrangement under which Jews and Christians paid a tax and kept their religion. Maimonides' family left, moving through Iberia and Morocco before settling in Egypt, where he became a physician, head of the Jewish community and the author of the Mishneh Torah, a complete restatement of Jewish law, and the Guide of the Perplexed, which sets out to reconcile that law with Aristotelian philosophy for a reader already troubled by the conflict.

Ibn Rushd stayed and prospered under the same dynasty. He served as judge in Seville and in Cordoba, was physician to the caliph, and produced commentaries on nearly the whole of Aristotle at three levels of detail. His Decisive Treatise argues that philosophy is not merely permitted but obligatory for those able to do it, and that where a demonstrated conclusion conflicts with the plain sense of scripture the scripture is to be read allegorically. His reply to al-Ghazali's attack on the philosophers is a line by line rebuttal titled the incoherence of the incoherence.

Late in life he fell from favour, his books were burned and he was banished. His work then had a stranger afterlife than either man could have expected: translated into Hebrew and Latin, he became simply the Commentator to the schoolmen of Paris, and Latin Averroism was condemned there while his influence in Arabic faded.