On the Holy Spirit

St. Ambrose - Bishop of Milan from 374 to 397; born probably 340, at Trier, Arles, or Lyons; died 4 April, 397. He was one of the most illustrious Fathers and Doctors of the Church, and fitly chosen, together with St. Augustine, St. John Chrysostom, and St. Athanasius, to uphold the venerable Chair of the Prince of the Apostles in the tribune of St. Peter's at Rome.

His dogmatic writings deal mostly with the divinity of Jesus Christ and of the Holy Ghost, also with the Christian sacraments. At the request of the young Emperor Gratian (375-383) he composed a defence of the true divinity of Jesus Christ against the Arians, and another on the true divinity of the Holy Ghost against the Macedonians.