1. Toulouse has a history of varied peoples.
Follow its growth, from Celts in BC, to Roman Empire also in BC, through Visigoths, Charlemagne, the Albigensian Crusade against the Cathars, a Christian group deemed heretic by Rome 1209-1243 at the fall of Montsegur, a last Cathar stronghold, and then the years of mop-up in the Pyrenees and elsewhere). The Crusade officially ended in 1229 with the Treaty of Meaux-Paris, against the Cathars. See http://southweststory.com/toulouse-short-history/ In 1233, however, the Inquisition began where the Albigensian Crusade left off, and with all the records carefully kept by the Church guiding the hunt for more heretics.
2. Toulouse is remembered for many of those, but least for its perhaps most important role: its killing of its own Catholic moderates.
With all those history-pushes and pulls, the least referenced, and perhaps the most important symbolically, is the role of Toulouse in the Albigensian Crusade, and the institution pitting authoritarianism against tolerance even among Catholics. Refresh recollections at .http://www.xenophongroup.com/montjoie/albigens.htm. For a timeline, see http://www.midi-france.info/19020113_ramonvi.htm/ The Church set its course against moderates at an early stage in Europe as elsewhere, with devastating consequences thereafter.
2.1. People rejected by the Church
Toulouse was the governmental seat of Count Raymond VI of Toulouse., a Catholic moderate who sympathized with the Cathars of his region, and refused to support Rome's Crusade to kill them off and confiscate their estates. He was accused of the assassination of the Pope's Legate, the Cistercian Pierre de Castenau. He was excommunicated -- twice during the Crusade -- and banished to England, where he died deprived of a Catholic burial. See http://www.midi-france.info/19020113_ramonvi.htm
2.2. His nephew, Raymond Roger Trencavel, Viscount of Carcassonne and also of Beziers and Albi, was a moderate Catholic as well. Count Raymond VI came to Raymond Roger and asked for support in opposing the Crusade. Raymond Roger, despite his governmental seat to the south, nearer the invasion points, failed to recognize the Roman threat and join with Count Raymond. Raymond Roger was killed.
3. This treatment by the institutional Church established an impermeable barrier against legitimacy of others' beliefs. Absolute intolerance, begun early with the militarization of the Church, its Crusades in the East, Charlemagne's killing of those who would not convert, grew with subsequent Inquisitions and terrorism. Feudalism, the firm division of human roles, was taught by the Church to be divinely ordained. The teachings of the Church were not to be challenged. See http://www.midi-france.info/19020113_ramonvi.htm/ Those who disagreed? Recant or die.
4. Toulouse: Death for death.
The spearhead against tolerance was himself killed, in his own battle against Toulouse.
In 1218, The Siege of Toulouse, Simon de Montfort was killed here. He had led the campaigns of the Pope and King against the prosperous Cathars, met his own death. Simon de Montfort had been periodically unstoppable, see analysis at http://www.briancreese.co.uk/cathars.htm/ Note that Cathar was merely a derogatory term, slang perhaps, and the proper name is Albigensian for the city of Albi where so many had their estates.
Two Raymonds. Sort them out to better understand the course of the Crusade against the Cathars. Count Raymond VI: http://historytimeshistory.blogspot.com/2011/11/cathar-heresy-count-raymond-vi-of.html; and Viscount Raymond Roger Trencavel , http://stephenosheaonline.com/book-tph-ex1.html
The legacy of no major area, crossroads for religion and commerce and politics, is simple. Nuance around with it, like a dance.