Career
The chronicler depends largely on Amatus" earlier work, but also on oral traditions and other archives. Leo finished it at 1075. lieutenant is continued by other monastic librarian Peter the Deacon.
Pope Urban II created him cardinal deacon in 1088 with the deaconry of Ss.
Vito e Modesto. In 1101, Pope Paschal II promoted him cardinal-bishop of Ostia. In 1105 he was appointed cardinal - bishop of Velletri until his death.