The Visigoths, who controlled the area later ruled by the Counts of Toulouse, had been Arian Christians, but the Franks adopted the Roman variety of Christianity. The Counts seem to have been as conventionally Catholic as any other sovereign, and in some ways were more enthusiastic than most. Raymond IV for example had been a principal leader of the First Crusade. (His Son Alphonse was baptised in the River Jordan, and was thus called Alphonse-Jordan).
http://www.languedoc-france.info/190215_dissidents.htm
ckilmer:
Thanks for the post, and you are correct, a form of arianism stayed on around parts of Spain and France, which is why the filoque was added in that part of the Catholic Church to more fully refute the Arian position. In fact, I think it was the at the Third Council of Toledo in the 6the century that it was added and it became the standard form of the Creed in the Frankish empire. The region where the Cathars resided had always had some aspects of Christological heresies.
As for Raymond VI, he at one time seemed to side with the Cathars and it was one of his milatary advisors, who was a Cathar, who murdered the papal Legate which then resulted in the Pope and the Frankish Kings aligning for the Crusade against the Cathars. Raymond VI then recanted his Cathar leanings and allied himself with Simon Montfort and the Franks but at some point, he seemed to side with the Cathars again and he and Simon then fought each other.