Peter the Deacon

Peter the Deacon (French: Pierre le Diacre) was the librarian of the abbey of Montecassino and continuator of the Chronicon monasterii Casinensis, usually called the Monte Cassino Chronicle in English. The chronicle was originally written by Leo of Ostia. According to both Chalandon and Lord Norwich, Peter is a poor historian and writer, much inferior to Leo.

For other uses, see Peter the Deacon (disambiguation).

Peter the Deacon
Born	1107
Died	1159  (aged 51–52)
Occupation	Librarian, archivist

Reputedly a descendant of the Counts of Tusculum, he was offered in 1115 to the monastery of Monte Cassino. About 1127 he was forced to leave the abbey and retired to the neighbouring Atina (Atina, Lazio), because he had supported Abbot Oderisius, who had been deposed by Pope Honorius II. In 1131 he returned to the abbey owing to the death of Pope Honorius. In 1137, he appeared before Emperor Lothair II, then in Italy, on behalf of his monastery. The sovereign was so pleased with him that he appointed him his chaplain and secretary, and would probably have attached him permanently to his person had not Abbot Wibald considered Peter's return necessary to the abbey.

In 1131 on his return to Monte Cassino Peter became librarian and keeper of the abbey archives, of which he compiled a cartulary (Registrum Petri Diaconi). Besides editing the existing chronicle of Monte Cassino (and introducing many falsehoods), he wrote several historical works: "De viris illustribus Casinensibus"; "De ortu et obitu justorum Casinensium"; "De Locis sanctis"; Disciplina Casinensis"; "Rhythmus de novissimis diebus".

Peter forged, under the name of Gordian, the Passion of St. Placidus. He is vain and occasionally untruthful, but an entertaining writer. His works are in Patrologia Latina, CLXXIII, 763-1144.

Sources

• Leo of Ostia. Chronicon Monasterii Casinensis.
• Chalandon, Ferdinand. Histoire de la domination normande en Italie et en Sicilie. Paris, 1906.
• Norwich, John Julius. The Normans in the South 1016-1130. Longmans: London, 1967.

 This article incorporates text from a publication now in the public domain: Herbermann, Charles, ed. (1913). "Petrus Diaconus". Catholic Encyclopedia. New York: Robert Appleton Company.