Born at Treves about 335, Ambrose belonged to an illustrious family of Roman magistrates. He was governor of Milan when called by the people to become bishop of the city. He was a great churchman who exerted a considerable influence. As an imperial counselor he resisted heresy; his unruffled energetic insistence brought the Emperor Theodosius to public penance for a horrible massacre perpetrated at Thessalonica. St. Ambrose had the glory of converting and baptizing St. Augustine whose conversion was to mean so much to the Church; both are honored among the four great Doctors of the Latin Church. St. Ambrose is the author of several liturgical hymns and it was he who introduced into the west the singing of psalms by alternate choirs. He died on April 4, 397.