Background
He was the son of Ponç I and succeeded his brother Ermengol IX within a year of their father's death.
He was the son of Ponç I and succeeded his brother Ermengol IX within a year of their father's death.
However, he detested this marriage and had it annulled, marrying Cecilia of Foix, daughter of Roger-Bernard II of Foix, in 1256. This was to be the source of great enmity and conflict between the houses of Béarn and Foix. The House of Barcelona supported the Bearnese.
In 1259, Álvaro breached his feudal obligations to the king of Aragon and brought down the royal wrath on his principality: the seneschal Pere de Montcada invaded and occupied Ponts. In 1267, the king of Aragon intervened again, this time in the legal dispute between Álvaro's two wives.