Peter II of Aragon was a king who ruled from 1196 to 1213. He was known for his efforts to unify the Crown of Aragon and expand its territories. His reign was marked by conflicts with neighboring kingdoms and the Albigensian Crusade, which aimed to eliminate heretical groups in southern France. Peter II was also notable for his role in the Battle of Muret in 1213, where he fought against the forces of Simon de Montfort. Unfortunately, he was defeated and killed in this battle, which significantly impacted the political landscape of the region. His legacy includes the strengthening of Aragon's influence in medieval Europe.