Constantine I of leprosy. The purpose of this forgery was to justify the Church's political claim on that territory.
Scholars believe that the document originated from a cleric in Rome or the Frankish empire.
The first official reference to it was made by Leo IX in a letter to Michael Cerularius, patriarch of Constantinople, in 1054 . In the 12th century, the document was used to support papal claims of temporal lordship. It was then thought to be genuine by friends and enemies of the papacy. The controversy over its legitimacy lasted until the 18th century. Now, it is generally accepted as a forgery by authorities in the Church history.