Peter was made Bishop of Ravenna around 433 — at a moment when the imperial court of the Western Empire had moved there and the city was the political capital of the dying empire. His brief, vivid sermons earned him in his own lifetime the surname Chrysologus, 'the Golden-Worded' — a Latin echo of John Chrysostom's Greek title.
He worked closely with Pope Leo the Great, refused to receive the heretic Eutyches when the latter sought refuge in the West, and built and rebuilt churches across Ravenna and Classe (its port). Many of the great Ravennate mosaics that survive today were begun or planned during his episcopate.
176 of his short Latin sermons survive — clear, brisk, immediately practical, and dense with biblical allusion. Pope Benedict XIII declared him a Doctor of the Church in 1729 on the strength of these sermons.