January 13 is the feast of St. Hilary of Poitiers (c. 310-367), bishop of Poitiers and Doctor of the Church. Born at Poitiers to a pagan noble family, he converted to Christianity after reading the Scriptures, and was made bishop of his city around 350. He became the foremost Western defender of the Council of Nicaea against the Arian bishops, and was exiled to Phrygia by the Emperor Constantius II in 356 for his refusal to condemn St. Athanasius.
His On the Trinity (c. 360), written during the exile, is the first Western theological treatise on the Trinity, and earned him the title Malleus Arianorum — the hammer of the Arians — and the doctorate of the Church, proclaimed by Pope Pius IX in 1851. He returned to Poitiers in 361 and continued the fight until his death in 367. From Poitiers, where he was bishop, to Rome, where his feast was kept from the early Middle Ages, the January 13 feast is the feast of the Western Athanasius.
