Peter was born in Imola about the year 400 and studied under Cornelius, bishop of Imola, who ordained him deacon. In 433, the archbishop of Ravenna died, and when a successor had been chosen by the clergy and people of Ravenna, they asked Bishop Cornelius to obtain confirmation of their choice from Pope Sixtus III. On his trip to Rome, Cornelius took his deacon, Peter, as his companion for the journey to Rome. For some reason known only to God, when the Pope met Peter, he chose him for the See of Ravenna instead of the one who had been selected by the clergy and people of Ravenna.
Peter was consecrated and was accepted somewhat grudgingly at first by both the clergy and the people. Peter, however, soon became the favorite of Emperor Valentinian III, who resided at Ravenna and was also highly regarded by Pope St. Leo the Great, the successor of Pope Sixtus.
There were still traces of paganism in Peter's diocese, and his first effort was to establish the Catholic faith everywhere, rooting out abuses and carrying on a campaign of preaching and special care of the poor. Many of his sermons still survive, and it is on the basis of these that he came to be known as Chrysologus, or "the golden word." In his concern for the unity of the Church, Peter Chrysologus opposed heresy wherever he found it.
When he knew his death was near, Peter returned to his own city of Imola and after urging great care in the choice of his successor he died at Imola about the year 450 and was buried in the church of St. Cassian. In 1729, Pope Benedict XIII declared him a Doctor of the Church.
O God, who madest the Bishop Saint Peter Chrysologus an illustrious preacher of thy incarnate Word: grant, through his intercession; that we may constantly ponder in our hearts the mysteries of thy salvation and faithfully manifest them in our lives; through Jesus Christ thy Son our Lord, who liveth and reigneth with thee, in the unity of the Holy Spirit, ever one God, world without end. Amen.