The Church of Saint-Sernin is named after Saint Saturnin, the first bishop and martyr of Toulouse whom lived in the first half of the third century. The construction of the Church was decided at the end of the eleventh century (around 1070). By 1118 the building was well established but later progressed at a much slower pace. The high octagonal 5-story bell-tower is totally made of brick and stone. The first three levels being of the Romanesque era, with a further two being added about 150 years later. The church is of enormous dimensions: 115 meters in length, a width of 64 meters at the transept, extending to 21 meters under the vault. The church is placed in the northern part of the city. In the middle of a large square with irregular shape, the imposing church forms the outline of a Latin cross. It was obviously designed in order to accommodate the swarms of pilgrims going to San Giacomo di Compostella who stopped off in Toulouse as the result of the great reputation of this church and its rich heritage of precious relics, such as those of Saint Saturnin and Saint James. With the aisles paralleling the nave and an ambulatory allowing easy access to the chapels radiating off the apse allowed the crowd to circulate in an orderly fashion. Because of the technical limitations of Romanesque architecture, windows were kept small. The principal interest of this church is thus the diversity of the styles that it manages to combine, mixing Romanesque and Gothic, stones and bricks. It is the largest Romanesque church known. .