Initially an acknowledgement of James IV's support for the foundation of the University, it became, in more troubled times, a symbol of the University's loyalty to the monarch under Charles I and II. Its closed shape indicates an Imperial Crown: a ruler with no feudal superior. Built by about 1520, it was blown down in 1633 and repaired almost to the original design. It is a daring piece of medieval engineering with only a few precedents, namely at Newcastle and St Giles' Cathdedral, Edinburgh.