St. Ambrose was probably born in 340 AD at Trier. He learned Greek, became a good poet and orator, and went to the bar. The emperor Valentinian made him governor of Liguria and Aemilia, with his residence at Milan.
Auxentius, an Arian, who held the see of Milan, died in 374 AD. The city was distracted by party strife about the election of a new bishop. To prevent, if possible, too outrageous a disorder Ambrose went to the church in which the assembly was held. There he made a speech, exhorting the people to proceed in their choice in the spirit of peace and without tumult. While he was speaking a voice cried out, 'Ambrose, bishop!', and the whole assembly took up the cry with enthusiasm. Although still a secular priest and catechumen, St. Ambrose was raised in eight days to the rank of bishop at the age of about 35.
Ambrose at once applied himself to the study of Holy Scriptures and the works of religious writers, particularly Origen and St. Basil. His personal life was one of simplicity and hard work.
He was a leader in the west of the battle against Arianism and paganism. He is one of the greatest Fathers of the Church, wrote many commentaries on Holy Scripture, dogmatic works, books on the sacraments and the duties of the clergy, and writings on monastic and moral life. He introduced antiphonal singing and other liturgical influences from the east into the west, and himself wrote hymns.
When Ambrose fell sick he foretold his death, but said he should live until Easter. On the day of his death he laid with his hands extended in the form of a cross for several hours, in constant prayer. The last thing he said was, "Arise! Make haste! He is going" and soon after he died. It was Good Friday, April 4, 397, and he was 57 years old. He was buried on Easter Day