St Ambrose of Milan

Ambrose was the Roman governor of Aemilia-Liguria when, entering the cathedral of Milan in 374 to calm the riotous election of a new bishop, a child's cry of 'Ambrose bishop!' was taken up by the whole crowd. Though still a catechumen, he was baptized and consecrated within days. He gave his wealth to the poor, mastered the Greek Fathers, and became the great teacher of the West: his preaching moved the young Augustine, whom he baptized at Pascha in 387. He defended the Church's independence, refusing the basilicas to the Arian court and barring the emperor Theodosius from the Eucharist until he did public penance for the massacre at Thessalonica — declaring that the emperor is within the Church, not above it. He fostered congregational hymn-singing, and his writings on Scripture, ethics, and the sacraments made him one of the four great Latin doctors.

St Ambrose of Milan is also one of the Church Fathers — read their biography, works, and verse-by-verse commentary.