John II of Aragon was a king who ruled from 1458 to 1479. He was born in 1398 and was a member of the House of Trastámara. His reign was marked by political struggles, including conflicts with the Catalan nobility and efforts to strengthen royal authority in Aragon. John II is also known for his role in the War of the Two Peters, a conflict with Castile. He was the father of Ferdinand II of Aragon, who later united Spain with his marriage to Isabella I of Castile. John II's legacy includes his contributions to the political landscape of medieval Spain.