Gothic architecture began with a series of experiments, which were conducted to fulfil specific requests by patrons and to accommodate the ever-growing number of pilgrims visiting sites that housed precious relics. Pilgrims in the high Middle Ages (circa 1000 to 1250 AD) increasingly travelled to well-known pilgrimage sites, but also to local sites where local and national saints were reputed to have performed miracles. The churches and monasteries housing important relics therefore wanted to heighten the popularity of their respective saints and build appropriate shrines for them. These shrines were not merely gem-encrusted reliquaries, but more importantly took the form of powerful architectural settings characterised by coloured light emitting from the large areas of stained glass. The use of stained glass, however, is not the only defining element of Gothic architecture and neither are the pointed arch, the ribbed vault, the rose window or the flying buttress, as many of these elements were used in one way or another in preceding architectural traditions. It was rather the combination and constant refinement of these elements, along with the quick response to the rapidly changing building techniques of the time, that fuelled the Gothic movement in architecture. Consequently, it is difficult to point to one element or the exact place where Gothic first emerged; however, it is traditional to initiate a discussion of Gothic architecture with the Basilica of St Denis (circa 1135–1344) and its patrons, Abbot Suger, who began to rebuild the west front and the choir of the church. As he wrote in his De Administratione, the old building could no longer accommodate the large volumes of pilgrims who were coming to venerate the relics of St Denis, and the solution for this twofold: a west façade with three large portals and the innovative new choir, which combined an ambulatory with radiating chapels that were unique as they were not separated by walls. Instead a row of slim columns was inserted between the chapels and the choir arcade to support the rib vaults. The result enabled visitors to circulate around the altar and come within reach of the relics without actually disrupting the altar space, while also experiencing the large stained-glass windows within the chapels. As confirmed by Suger, the desire for more stained-glass was not necessarily to bring more daylight into the building but rather to fill the space with a continuous ray of colorful light, rather like mosaics