Bp. of Milan and one of the four traditional Doctors of the Church. He was governor of Aemilia-Liguria, when in 373 or 374, on the death of the Arian bishop, Auxentius, the Milanese laity demanded that Ambrose should succeed him, though he had not yet been baptized. As bishop he was famous as a preacher and was a zealous upholder of orthodoxy against Arianism. He was partly responsible for the conversion of Augustine (386). He exercised a remarkable degree of authority in his dealings with successive Emperors, excommunicating Theodosius for a massacre in 390, and he maintained the independence of the Church from the civil power. Apart from the De Sacramentis (q.v.), his most notable work was the De Officiis Ministrorum, a treatise on Christian ethics, with special reference to the clergy. He also wrote Latin hymns (q.v.), and it was through his influence that hymns became an integral part of the liturgy of the W. Church. Feast day, 7 Dec.; in the BCP calendar, 4 Apr.