Gaston VII, Viscount of Béarn

Towards the end of his life he reneged and declared as his heir his youngest daughter, Guillemette, but upon his death Béarn was seized by Margaret's husband, Roger-Bernard III of Foix.

Gaston was highly reputed as a warrior, staunch defender of the Béarnais, ally of the French, and enemy of the English.

However, in 1252 Gaston once more rebelled when he allied with Alfonso X of Castile, who had laid claim to the Duchy of Gascony.

This time Henry III pursued a diplomatic strategy; he arranged a marriage between his son Edward and Alfonso's daughter Eleanor.

[2] Between 1245 and 1250 Gaston married Martha, Viscountess of Marsan (also called Amata of Mastas; died 1270/3), daughter of Boson de Mathe, lord of Cognac, and Petronilla of Bigorre.