Liber Pontificalis
The modern interpretation, following that of Louis Duchesne, is that the "Liber Pontificalis" was gradually and unsystematically compiled, and that the authorship is impossible to determine, with a few exceptions (e.g. the biography of Pope Stephen II (752–757) to papal "Primicerius" Christopher; the biographies of Pope Nicholas I and Pope Adrian II (867–872) to Anastasius). Duchesne and others have viewed the beginning of the "Liber Pontificalis" up until the biographies of Pope Felix III (483–492) as the work of a single author, who was a contemporary of Pope Anastasius II (496-498), relying on "Catalogus Liberianus", which in turn draws from the papal catalogue of Hippolytus of Rome, and the "Leonine Catalogue", which is no longer extant. Most scholars believe the "Liber Pontificalis" was first compiled in the 5th or 6th century.