William II, Viscount of Béarn

The main thrust of his policy was the affairs of the Aragonese court, in which several families vied for influence over the young King James I.

This act marked the departure of Bearn from within the Aragonese domain and the start of its progressive submission to England.

Back in Catalonia, he played a leading role in the council held in Salou which planned the conquest of Majorca.

The troops having landed, they engaged in the battle of Portopí, thus beginning the conquest of Majorca.

In the division following the conquest of the island by the Crown of Aragon, the municipality of Costitx was given to Guillermo II de Bearn[4] and thus passed to his heirs.

Guillem II in a fresco on the walls of the house once belonging to Berenguer d'Aguilar de Barcelona. His shield shows a combination of the arms of Montcada and those of Béarn.
The Montcada arms marshalled with the bars of Aragon on a monument near where Guillermo and his nephew, Ramón, died in combat during the conquest of Majorca .