ANASTASIO BIBLIOTECARIO. – Born probably in Rome around 817, he received a solid cultural education in Latin and Greek in the urban monasteries. Created cardinal priest of S. Marcello by Leo IV around 847, he was excommunicated and struck with anathema by the same pope at a synod held in Rome on 19 June 853 for having abandoned his post and refused to return to it despite repeated appeals. Ambitious and possessed of a very flexible conscience, he belonged to the imperial party in the hope of ascending the papal throne. In 855, immediately after the election of Benedict III, he returned to Rome with a strong army, but his attempt to occupy the Lateran failed. Defeated, he received the Pope’s pardon, who reduced him to the lay state. When Nicholas I ascended the papal throne in 858, A. returned to favour and became the Pope’s adviser, a position he retained under the subsequent pontificates of Adrian II and John VIII as well, becoming one of the most important figures of the period. He played a prominent part in the controversies with Photius, which opened the schism of the Eastern Church. He attended the final session of the Eighth Ecumenical Council at Constantinople (869–70), a copy of whose Acts he brought back to Rome and, at the invitation of Adrian II, translated into Latin (871); this is the only copy preserved. Later (873), on the orders of John VIII, he also translated into Latin the Acts of the Seventh Ecumenical Council, held at Nicaea (787). After 877 A.’s name no longer appears in the documents, and we do not know the year of his death.
Almost all of A.’s works are Latin translations from the Greek. Among these, the following are of particular relevance to ecclesiastical history: Versiones gestorum synodorum VII et VIII (Pl. 129, 205–542, 27–196); Collectanea, that is, translations concerning the question of Monothelitism and Pope Honorius I (ibid., 557–690); Acta s. Martini papae (ibid., 585–609); Historia ecclesiastica (ed. C. De Boer, Theophanis Chronographia, II, Leipzig 1885, pp. 31–346), expanded in accordance with Cassiodorus’s tripartite history by incorporating the histories of Nicephorus, Syncellus, and Theophanes, translated into Latin by A. The remainder of the works consists of translations of lives of Greek saints. A. prefaced each of these with explanatory prefaces or letters (MGH, Epist., VII, pp. 395–442), some of which are of singular importance,
especially those relating to the Acts of the Seventh and Eighth Councils (ibid., pp. 403–18).
Onofrio Panvinio wrongly attributed the Liber Pontificalis to A.; this attribution was often repeated up to the present day. It seems instead beyond doubt that A. was the author of the life of Nicholas I, although there are scholars who dispute this.