The Liber Pontificalis (Latin for 'pontifical book' or Book of the Popes) is a book of biographies of popes from Saint Peter until the 15th century. The original publication of the Liber Pontificalis stopped with Pope Adrian II (867–872) or Pope Stephen V (885–891), but it was later supplemented in a different style until Pope Eugene IV (1431–1447) and then Pope Pius II (1458–1464). Although quoted virtually uncritically from the 8th to 18th centuries, the Liber Pontificalis has undergone intense modern scholarly scrutiny. The work of the French priest Louis Duchesne (who compiled the major scholarly edition), and of others has highlighted some of the underlying redactional motivations of different sections, though such interests are so disparate and varied as to render improbable one populariser's claim that it is an "unofficial instrument of pontifical propaganda."
The title Liber Pontificalis goes back to the 12th century, although it only became current in the 15th century, and the canonical title of the work since the edition of Duchesne in the 19th century. In the earliest extant manuscripts it is referred to as Liber episcopalis in quo continentur acta beatorum pontificum Urbis Romae ('episcopal book in which are contained the acts of the blessed pontiffs of the city of Rome') and later the Gesta or Chronica pontificum.
