Berenguer IV was a prominent medieval nobleman who served as the Count of Barcelona from 1131 until his death in 1142. He was a member of the House of Barcelona and played a significant role in the expansion of the county's territory. His reign was marked by military campaigns against the Moors in the Iberian Peninsula, which helped to consolidate Christian control in the region. In addition to his military achievements, Berenguer IV is 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 medieval Spain.