 The irregular west front exists because the cathedral consists of two incomplete churches.The first dating from the early 13th century (1210 to 1220), 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 (19 metres wide).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 style from 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.