Amiens Cathedral: The expensive visual refinement of Amiens in terms of its proportions, decoration, detail carving (stringcourse, sculpture, capitals, elaborate triforium and clerestory tracery, pinnacles) demonstrated the prestige of the diocese in competition with other urban cathedrals such as Reims and Chartres. The enlarged choir was needed to accommodate the large number of canons attached to the cathedral (their choir stalls lined the straight bays of the choir) and indicate the tremendous wealth of the diocese (each canon possessed a prebend or yearly income usually paid for by rents and land holdings). It also demonstrated the high level of technically proficiency achieved in the craft of masonry during the thirteenth century. But more fundamentally, Gothic architecture was interested in light--great expanses of stained glass. This is related to the belief in light as a transcendental vehicle in religious devotion. The primary goal of the Gothic builder was to create a light-filled space (related to beliefs in Dionysian light metaphysics as discussed with Saint-Denis). The sophisticated structural engineering was a response to that need. (Necessity is the mother of invention). Thus Gothic builders used pointed arches, flying buttresses, and ribbed vaults as solutions to the problem of voiding the wall space in order to create taller and more luminous spaces