Saint Justin Martyr c.AD 100-c.AD 165, Christian apologist, called also Justin the Philosopher. Born in Samaria of pagan parents, he studied philosophy, and after his conversion in Ephesus to Christianity at about the age of 38, he went from place to place trying to convert men of learning by philosophical argument. He opened a school of Christian philosophy at Rome, where he and some disciples were finally martyred under Marcus Aurelius. Of his writings (in Greek), only two undisputed works remain, the Apology (with an appendix called the Second Apology ) and the Dialogue. The Apology is a learned defense of Christians against charges of atheism and sedition in the Roman state; it contains an exposition of Christian ethics and invaluable records of the customs and practices of 2d-century Christianity. The Dialogue sets forth in the form of an argument with Trypho (or Tryphon) the Jew a philosophic defense of Christian beliefs, particularly with reference to Jewish writings; it has references to the Gospels that have been of much interest to students of the Bible. Feast: Apr. 14.