Santa Maria in Domnica
With the death of Pope Agapetus II in November 955, Octavian, who was the cardinal deacon of Santa Maria in Domnica, was elected his successor on 16 December 955. His adoption of the apostolic name of John XII was the third example of a pontiff taking a regnal name upon elevation to the papal chair, the first being John II (533–535) and the second John III (561–574). Right from the start, in relation to secular issues, the new pope issued his directives under the name of Octavian, while in all matters relating to the Church, he issued papal bulls and other material under his pontifical name of John.