St. Ambrose

340-397.  Bishop of Milan and Doctor of the Church.  One of the four great Western Fathers (with SS. Augustine, Jerome and Gregory).  Catholic Encyclopedia article here.  Wrote many exegetical works in addition to being one of the first great Christian hymn-writers.  He wrote a series of exegeses of the beginning of Genesis: six books on the Hexameron (six days of creation), and books on Paradise, Cain and Abel, Noe and the Ark, Abraham and Jacob.