William the Old (Latin: Gulielmus Senex; died 1168)[1] was a 12th-century prelate who became one of the most famous bishops of Orkney.
[2] There is no contemporary evidence of his episcopate until a letter of Pope Honorius II in 1128, which even then does not name William specifically, but rather only mentions a bishop holding office at the same time as Radulf Novell.
[4] Bishop William was a promoter of the cult of St Magnus, and was allegedly witness to some posthumous miraculous activity of the former earl.
William had St Magnus' relics transferred to Kirkwall, fixing the episcopal seat at this location and, with the assistance of Earl Rognvald Kali Kolsson, constructing a new cathedral there.
It was probably for these reasons that William was remembered in later Orcadian tradition, saga and ecclesiastical, as the founding bishop of Orkney.