Ambrose refused, and would not yield to their prayers, whereupon they carried their petition to the Emperor Valentinian. It was very pleasing to this Prince that those he had appointed as judges should be chosen Bishops, as also the Prefect Probus, who had, as it were prophetically, said to him when he appointed him, Go and govern them more like a Bishop than a Judge. When the will of the Emperor was added to the desire of the people, Ambrose yielded, and received Baptism (for hitherto he was only a Catechumen), Confirmation and Communion, and then the several Orders on successive days, till on the eighth day, which was the 7th of December, the weight of the Episcopate was laid upon his shoulders. Being made Bishop, he shewed himself a stout upholder of the Catholic faith, and the discipline of the Church, and turned to the truth great numbers of Arians and other heretics, and, among them, he begat in Christ Jesus that burning and shining light of the Church, Augustine.
After the murder of the Emperor Gratian, Ambrose was sent as an ambassador to Maximus, by whom he had been slain, and, as he refused to repent, the Bishop renounced his communion. After the massacre which the Emperor Theodosius had commanded at Thessalonica, he refused to permit that Prince to enter a church. The Emperor pleaded that he was no worse than David, who had been guilty of adultery and murder, to which Ambrose answered him, As thou hast followed him in his sin, follow him also in his repentance. Then Theodosius humbly did public penance laid upon him by the Bishop. At length the Saint was worn out with his continual labour and care for the Church (for the which also he composed many excellent books), and foretold that the day of his death was at hand, though he had not then fallen into his last sickness. As he lay dying, Honoratus, Bishop of Vercelli, heard a voice from God three times crying to him that the hour of Ambrose's departure was come, whereupon he went to him quickly, and gave him the sacred Body of our Lord. When he had received it, the Saint, still praying, with his hands stretched out in the form of a cross, gave his spirit to God, upon the 4th day of April, in the year of Christ 397.