Peter the Great (, ; 1239, in Valencia – 11 November 1285) was the King of Aragon (as Peter III) of Valencia (as Peter I), and Count of Barcelona (as Peter II) from 1276 to his death. At the invitation of some rebels, he conquered Sicily and became its king in 1282, pressing the claim of his wife, Constance. He was one of the greatest of medieval Aragonese monarchs.