"Rayonnant Gothic" maximised the coverage of stained glass windows such that the walls are effectively entirely glazed; examples are the nave of Saint-Denis (1231–) and the royal chapel of Louis IX of France on the Île de la Cité in the Seine – the Sainte-Chapelle ("c".1241–8). The high and thin walls of French "Rayonnant Gothic" allowed by the flying buttresses enabled increasingly ambitious expanses of glass and decorated tracery, reinforced with ironwork. Shortly after Saint-Denis, in the 1250s, Louis IX commissioned the rebuilt transepts and enormous rose windows of Notre-Dame de Paris (1250s for the north transept, 1258 for the beginning of south transept). This first 'international style' was also used in the clerestory of Metz Cathedral ("c".1245–), then in the choir of Cologne's cathedral ("c".1250–), and again in the nave of the cathedral at Strasbourg ("c".1250–). Masons elaborated a series of tracery patterns for windows – from the basic "geometrical" to the "reticulated" and the "curvilinear –" which had superseded the lancet window. Bar-tracery of the "curvilinear, flowing", and "reticulated" types distinguish "Second Pointed" style.