Origen, the Christian theologian and exegete of the Bible, was the foremost member of the catechetical school at Alexandria. Born of Christian parents in Alexandria, he was made head of a Christian school there in 204. He taught until 231, when conflict with the bishop forced him to leave for Caesarea in Palestine, where he taught until his death. He apparently heard lectures by Ammonius Saccas, founder of Neoplatonism, although he regarded philosophy as essentially preparatory to theology in the same way that other studies were prerequisite to philosophy itself. However, the influence of philosophy (primarily Platonic but also Stoic) on his thought was highly significant; it can be observed much more clearly in his presuppositions and arguments than in explicit quotations, which are relatively unusual except in the apologetic treatise Contra Celsum. The most important of his voluminous writings are De Principiis, a treatise on...