Earl's Bu, in Orphir, has the foundations of a 12th-century manor house belonging to the Norse earls of Orkney. There are also the remains of St Nicholas’ Church, a unique circular building that was originally 9m in diameter. Built before 1136 and modelled on the rotunda of the Church of the Holy Sepulchre in Jerusalem, it was popular with pilgrims after the capture of the Holy Land during the First Crusade.