Simon had interpreted this act as a gift and had been fought by the heiress of the county, Alix de Montfort assisted by her half-sister, Martha, wife of Gaston VII Viscount of Béarn.
To prevent Guyenne and Gascony from rebelling, Henry III recalled Simon de Montfort and appointed John Grailly in his place.
Gaston VII then invaded the county, forcing Eschivat to defend it, seeking the assistance of Prince Edward of England and the alliance of Count Roger IV of Foix he married the daughter Ines (1256).
In 1258, war resumed in the region and Eschivat agreed to temporarily surrender the County of Bigorre to Simon de Montfort, this time to end the conflict.
Soon after, Simon de Montfort rebelled against King Henry III, and Eschivat helped Gaston VII regain Bigorre.