Tertullian (Quintus Septimus Florens Tertullianus) (tûrtŭl´yən), c.160–c.230, Roman theologian and Christian apologist, b. Carthage. He was the son of a centurion and was well educated, especially in law. Converted to Christianity c.197, he became the most formidable defender of the faith in his day. His Latin is vigorous and effective and reflects his juridical training. Sentences of his that have become proverbial are
"The blood of martyrs is the seed of the church,"
"It is certain because it is impossible"
(often quoted incorrectly as
"I believe it because it is impossible"
). Some of Tertullian's opinions differed from the main stream of Christian thought, particularly his more rigorous view of sin and its forgiveness. After long defending the Montanists (see Montanism), he left the church (213) to join them; he later established his own sect, known as Tertullianists. Tertullian's most important writings are Apologeticus, Ad Nationes, and De Praescriptione.
See studies by T. D. Barnes (1971) and R. D. Sider (1971).