The Convento de Cristo is a testament to the Templars' architectural abilities. The octagonal church was inspired by the Islamic Dome of the Rock shrine in Jerusalem, used by the Templars as their base of operations. The Dome of the Rock is located on the Temple Mount, where the Temple of Jerusalem stood prior to its destruction in 70 A.D., and the Templars believed the Dome of the Rock was a remnant of the ancient Temple from which their name derives. The order incorporated features of the shrine into their imagery and architecture, including the seals of Grand-Masters. The architecture of the Church of the Holy Sepulchre may have also served as a model. The sepulchre itself stands in an elaborate structure within the rotunda (rotunda - 35 m diameter), surrounded by a group of three columns between four pairs of square piers columns supporting an ornamented, domed roof. It is possible that the 4th-century rotunda's columns were removed from their original location on the façade of the Roman temple. Renovation of the piers exposed evidence that the columns had originally been much higher and that the Crusaders cut them in half for use in the 12th-century rotunda.