Maimonides

Moses ben Maimon was born in Córdoba, son of a rabbinical judge. In 1148 the fanatical Almohads took the city and Jews were forced to convert or flee. The family wandered for years, to Fez in Morocco, then through Palestine to Fustat in Egypt. His brother, a jewel merchant, was lost at sea in the Indian Ocean with the family fortune, and from then on Maimonides lived by medicine, eventually as physician to the court of Saladin.

He was at once jurist, physician and philosopher. The fourteen-volume Mishneh Torah systematised the whole of Jewish law in Hebrew and remains an authoritative code. His 'Thirteen Principles' entered the Jewish prayer book. As a physician he wrote ten medical works, on subjects from asthma to poisons, in a notably cautious style.

The Guide for the Perplexed, written in Arabic for a student, is for those who believe in the Torah, have studied philosophy and find themselves torn. He argues that the Bible's human descriptions of God are all metaphor and that God can only be spoken of negatively: not what he is, only what he is not. He accepted most of Aristotle's natural philosophy but held that the eternity of the world could not be proved, and so kept creation. Translated into Hebrew and Latin, the book was cited constantly by Aquinas, and Spinoza formed his own thought in wrestling with it.