is an interesting article on the episcopal ordination of St. Ambrose, in the Fourth Century. He accomplished much in his quarter-century as Bishop of Milan.
From the article:
In his twenty-five years as bishop, Ambrose became one of the leading figures of the early church. He worked to remove Arian influence in Milan, promoted the incorporation of Greek learning into Catholic thought, introduced new music and wrote hymns, gained renown for his strict morality, and tried to assert the church’s moral authority by criticizing actions by different emperors that he thought reprehensible.