In 1209 the Albigensian Crusade (“Occitan War”) visited the south of France. Pressured by Odo III, Duke of Burgundy, and Hervé, Count of Nevers, the viscount of Narbonne bowed to a Papal command and assisted the crusaders with money, supplies and castles. Aimery was present at Béziers when Agnes, widow of the last viscount, Raymond Roger Trencavel, handed the viscounty of Béziers over to Simon de Montfort IV. The next year (1210), Aimery assisted Simon in the siege of Minerve, but he refused, on account of the wishes of his subjects, to participate in the siege of Castelnaudary.