Born around AD 100, St. Justin (also known sometimes as Justin Martyr) was a philosopher who converted to Christianity around AD 135. After his conversion, he turned his philosophical mind toward defending some of the "mysteries" of Christianity like baptism and the Eucharist. What made Justin different is that he made a special effort to explain Christianity to Pagans and Jews, rather than other Christians. This earned him renown as a defender of Christianity.
Taking his role of defender to a new level, he publicly debated Rabbis, Stoics, and eminent pagans with vigor. He authored many books on rational Christianity, though only two of his Apologetics and his Dialogue of Trypho remain. Justin's vociferous public defense of Christianity caught the attention of the local pagan authorities, and in AD 165 he was beheaded along with four other Christians by Rusticus, the local Roman prefect. When faced with execution, Justin was asked for the last time if he would obey the law and sacrifice to the pagan gods. His reply: "Through prayer we can be saved on account of our Lord Jesus Christ, even when we have been punished, because this shall become to us salvation and confidence at the more fearful and universal judgment-seat of our Lord and Savior."
If St. Justin had taken the Spiritual Types Test, he probably would have been a Sage. Justin's feast day is celebrated on June 1.