Pseudo-Isidorian Decretals

The Pseudo-Isidorean Decretals (or False Decretals) are a set of extensive, influential medieval forgeries written by a scholar (or group of scholars) known as Pseudo-Isidore. The authors, using the pseudonym of Isidore Mercator, were probably a group of Frankish clerics writing in the second quarter of the 9th century. To defend the position of bishops against metropolitans and secular authorities, they created documents purportedly authored by early popes and council documents.

Historical background

The Carolingian Empire in the second quarter of the 9th century set the stage for the forgers. Although Louis I the Pious was deposed by his sons in the early 830s, he soon regained the throne. Archbishops and bishops played important roles, imposing penance on Louis for his allegedly-sinful life and paving the way for his removal. When Louis regained the throne, some church dignitaries were stripped of their bishoprics and exiled.

Content

The Pseudo-Isidorian Decretals and fictitious letters from Clement to Gregory the Great were incorporated in a 9th-century collection of canons purportedly by the pseudonymous Isidore Mercator. Collections of canons were commonly made by adding new matter to old; the forgers of the Pseudo-Isidore collection took as the basis of their work the Hispana Gallica Augustodunensis, interpolating their forgeries with the genuine material to provide credibility by association. The Liber Pontificalis was used as a historical guide, and furnished some subject matter. The Pseudo-Isidorian collection includes an earlier (non-Pseudo-Isidorian) forgery, the Donation of Constantine.