Clement of Alexandria

Clement is the Christian who took Greek philosophy seriously without apologising for it. He thought Plato was a kind of pre-Christian preparation for the gospel — that philosophy was to the Greeks what the Law was to the Jews, a tutor leading them to Christ. His Stromateis ('Miscellanies') is exactly what the title says: scattered notes on philosophy, scripture, ethics, and the inner life of the educated Christian. He taught Origen, which is enough by itself to put him on this map. Without Clement there's no Alexandrian school, no Origen, no Christian intellectual tradition that takes pagan thought as raw material rather than enemy.