Peter IV of Aragon, also known as Peter the Ceremonious, was the King of Aragon from 1336 until his death in 1387. He was a member of the House of Barcelona and played a significant role in the political landscape of medieval Spain. His reign was marked by efforts to strengthen the kingdom and expand its territories, particularly through military campaigns. Peter IV is also known for his contributions to the Crown of Aragon and the establishment of a more centralized government. He faced challenges from both internal factions and external threats, including conflicts with Castile. His legacy includes the promotion of trade and culture, which helped to enhance the prosperity of his realm.