The irregular west front exists because the cathedral consists of two incomplete churches. The first dating from the early 13th century, which includes the rose window from 1230, is the very first manifestation of Southern French Gothic architecture introduced to fight Cathar heresy through preaching, it probably was the widest nave in Western Europe at its completion. The other begun in about 1272, on a new plan and a different axis, which was later abandoned, although by 1445 a triforium had been added to the choir and a Flamboyant west portal had been inserted, is in a Gothic stylefrom the north of France to give pledges to the royal power that had taken possession of the city after the Albigensian Crusade and the extinction of the lineage of the Counts of Toulouse. It is off-center because the architect took care to save the baptismal chapel north of the entrance. An oblong tower, composed of a Gothic portion on Romanesque foundations, and capped by a 16th-century gable belfry, completed the west façade. Also in the 15th century the nave and choir vaults were unsymmetrically connected, while in 1609, after a fire, the choir vault was rebuilt. It was not until the 1920s that its north wall was cleared of abutting buildings and a doorway added, similar in style to the west entrance. The interior is as disconcerting as the exterior because the two sections are not on the same axis and juxtapose two styles of Gothic architecture. A massive round pillar, built at the beginning of the 16th century in an attempt to begin the transept, now stands incongruously between the two parts, lining up with the center of the nave in the west, and with the south pillars of the choir in the east. The vast proportions of the five-bay choir, with ambulatory and radiating chapels, dwarf the older nave. Of the 15 chapels, the oldest date from 1279–86, but the majority were completed during the 14th century. Most of the stained glass is 19th-century, but there is glass from almost every century beginning with the end of the 13th in the Saint Vincent de Paul chapel. This is the oldest stained glass in Toulouse. The interesting choir stalls whose decoration includes pagan and mythological subjects were carved in walnut in 1610-13 by Pierre Monge of Narbonne. The walnut case of the organ was carved at the same time, rising some 17 meters above the floor. Restored in 1868 by Cavaillé-Coll and in 1976, the organ is often used for concerts. The beautiful, but worn, tapestries by Jean du Mazet, and the Baroqueretable of the high altar are also of particular note.
