Although there has been a church on the site since ca. 1130, the present building dates principally from the 14th century. The five nave bays, the transepts and four of the five choir bays were all built ca. 1365-1395. Additions including aisles, the distinctive crown spire and the raising of a clerestory over the nave were all made by 1500. The exterior was inappropriately refaced in ashlar by William Burn in 1829-1833. Most of the stained glass dates from 1872-1883, financed by William Chambers; this renovation also created a single interior space. The North and West windows are 20th century. St. Giles' was only a cathedral in its formal sense (i.e. the seat of a bishop) for two periods during the 17th century (1635-1638 and 1661-1689); it is now Church of Scotland (Presbyterian). The Order of the Thistle Chapel was designed by Robert S. Lorimer and finished in 1911. It contains stalls for the 16 knights, the Sovereign' s stall and two Royal stalls.