The Diploma Ottonianum (also called the Pactum Ottonianum, Privilegium Ottonianum or simply Ottonianum) was an agreement between Pope John XII and Otto I, King of Germany and Italy. It confirmed the earlier Donation of Pepin, granting control of the Papal States to the Popes, regularizing Papal elections, and clarifying the relationship between the Popes and the Holy Roman Emperors.