Ramón Berenguer IV was a prominent medieval nobleman who ruled as the Count of Barcelona from 1131 until his death in 1162. He was a key figure in the expansion of the County of Barcelona and played a significant role in the consolidation of Catalonia. His reign is noted for the unification of various territories and the strengthening of local governance. In 1150, Ramón Berenguer IV married Petronilla of Aragon, which helped to forge a powerful alliance between Catalonia and the Kingdom of Aragon. This marriage laid the groundwork for the eventual creation of the Crown of Aragon, significantly influencing the political landscape of the Iberian Peninsula during the Middle Ages.