Ambrose( 340 - 4 April 397 )
Aurelius Ambrosius , better known in English as Saint Ambrose , was a bishop of Milan who became one of the most influential ecclesiastical figures of the 4th century. He was the Roman governor of Liguria and Emilia, headquartered in Milan, before being made bishop of Milan by popular acclamation in 374. Ambrose was a staunch opponent of Arianism, and has been accused of fostering persecutions of Arians, Jews, and pagans.
Traditionally, Ambrose is credited with promoting "antiphonal chant", a style of chanting in which one side of the choir responds alternately to the other, as well as with composing Veni redemptor gentium, an Advent hymn.
Ambrose was one of the four original Doctors of the Church, and is the patron saint of Milan. He is notable for his influence on Augustine of Hippo.