 Like most of the baronage of southern France, Gaston did not participate in the Third Crusade, because of the grand conflict between the crown of Aragon on the one hand and the county of Toulouse on the other.Gaston was firmly in the Aragonese camp.In 1194, a territorial dispute with the viscounty of Dax was resolved with the exchange of Mixe and Ostabarret, Ostabat, in return for the city of Orthez from Dax.