Patrimony of St. Peter

The "Patrimony of St. Peter" refers to the territories in central Italy over which the pope held sovereignty from 756 to 1870, collectively known as the Papal States. These lands included modern-day regions like Lazio, Umbria, and Marche.

The origins of these territories trace back to the 4th century when popes acquired property around Rome, known as the Patrimony of St. Peter. As the Western Roman Empire weakened, the popes' influence grew, and they became protectors of the region against invasions. The formal establishment of the Papal States occurred in the mid-8th century when Pope Stephen II appealed to the Frankish ruler Pippin III for aid against the Lombards. Pippin's subsequent donation of lands in 756 formed the basis for papal temporal power. The extent and control over these territories varied significantly over the centuries, facing challenges from local nobility, emperors, and later, revolutionary movements and Italian unification efforts. The Papal States ultimately ceased to exist in 1870 when Rome was annexed by the newly formed Kingdom of Italy.1