Peter II died fighting the anti-Catharist crusaders at the Battle of Muret in 1213. His heir and successor, James I, a minor, was taken captive by Simon IV de Montfort, the Earl of Leicester. An army was soon assembled at Narbonne with the support of Viscount Aimery III to recover the captive king and avenge the dead king. Sancho and his son Nuño were among the leading men present. The situation was diffused, however, by the papal legate Peter of Benevento, who secured James's release.