Berenguer IV was a prominent medieval nobleman, born in 1114, who became the Count of Barcelona in 1131. He was a member of the House of Barcelona and played a significant role in the expansion of Catalonia during the 12th century. His reign was marked by efforts to consolidate power and promote trade and agriculture in the region. In 1150, Berenguer IV married Petronilla of Aragon, which united the crowns of Aragon and Catalonia. This marriage laid the foundation for the future Crown of Aragon, significantly influencing the political landscape of the Iberian Peninsula. Berenguer IV's legacy is remembered for his contributions to the growth and stability of Catalonia.