Anastasius (Bibliothecarius), librarian of the Vatican, and abbot of St. Maria Trans- Tiberim at Rome, a celebrated and learned writer of the ninth century. The dates of his birth and death are unknown. He was on terms of intimacy with the learned men of his age, especially with Photius and Hincmar. He was present in 869 at the eighth council of Constantinople, where Photius was condemned. He translated the Acts of the Council from Greek into Latin. He wrote a Historia Ecclesiastica (Paris, ed. by Fabrotti. 1649, fol.); but the most important of his writings is a History of the Popes, under the title De Vitis Romanorum pontificum, a Petro Apostolo ad Nicolaunz I, adjectis vitis Hadriani II et Stephani IV (Romae, 1718-1735, 4 vols. fol., and several other editions). — Cave, Hist. Lit. ann. 870; Hoefer, Nouv. Biog. Generale, 2, 479.