The period of intense papal–imperial hostilities coincided with equally turbulent events taking place in the Midi, as Count Raymond VII of Toulouse struggled to recover his former lands. His supporters hoped that Frederick could be drawn to intervene against the French in the defence of his rights in the kingdom of Arles, and their hatred of the clergy there naturally merged with the anticlerical stance of Frederick's own supporters. Occitan troubadours voiced outrage at what they saw as a perversion of the true purpose of crusading, and contrasted the call of the Holy Land with the ‘false crusade’ of the French against Toulouse. They were not entirely unsupported by their northern colleagues.

By 1224 Raymond VII had retaken possession of many castles captured by the French, and restored them to their exiled holders. At the council of Bourges on 30 November 1225 he was excommunicated, and on 30 January 1226 Louis VIII took the cross and marched down the Rhone valley at the head of a powerful army, accompanied by the papal legate Romain de Saint-Ange. They reached Avignon after encountering no resistance on the way. As a result of an obscure misunderstanding, the city first yielded to the king, then defied him during a long hot summer of siege. Faced with growing discontent in his army as a result of the exorbitant cost of food and the spread of dysentery, Louis attempted an assault on the city, but failed. The defeat was generally ascribed to the treachery of some of his barons, particularly to the trouvere Thibaut de Champagne, who, according to Jonathan Sumption, had only joined Louis’ crusade under duress. He had relatives inside Avignon and apparently remained in constant contact with them throughout the siege. Suffering from hunger and unaware of the gravity of Louis’ situation, the Avignonese surrendered on 9 September, and more and more of Raymond's supporters submitted to the king, who marched triumphantly through the Languedoc.

The response of Tomier and Palaizi to the imminent arrival of the king's army at Avignon's city walls highlights the bitterness in the region at the corruption of the very notion of crusade (BdT 442.1).