Maimonides (Moses ben Maimon) was born in Cordoba, Spain, but spent his most productive years in Cairo, where he served as a royal physician. The Arabic cultural environment brought him into contact with classical Greek philosophy. Maimonides fused neo-Aristotelian philosophy with the Jewish legal tradition into a systemic whole. His main philosophic work, "The Guide for the Perplexed," is an apologetic appeal to rationalists troubled by the corporeality of God in the biblical accounts. He proposes a philosophic interpretation of the Bible that emphasizes abstract and spiritual meaning over literal interpretation. Maimonides formulated the 13 principles of faith that represent the irreducible core of Judaism.