Count Ramon Berenguer IV of Barcelona was a prominent medieval nobleman who ruled from 1131 to 1162. He was a member of the House of Barcelona and played a crucial role in the expansion of the County of Barcelona. His reign is noted for the consolidation of power and territorial gains, particularly through strategic marriages and military campaigns. Ramon Berenguer IV is best known for his marriage to Petronilla of Aragon, which united the County of Barcelona with the Kingdom of Aragon. This alliance laid the groundwork for the future Crown of Aragon, significantly influencing the political landscape of the Iberian Peninsula during the Middle Ages.