Ramon Berenguer IV, also known as the Saint, was born in Barcelona either in 1101 or 1102 and died on August 6th 1162 in Borgo San Dalmazzo in Piedmont, Italy.
He was Count of Barcelona, Girona, Osona, and Cerdanya (1131-1162) and Prince Regent of Aragon and Count of Ribagorça (1137-1167). He was also Regent of Provence, where he was known as Ramon Berenguer III.
He is best known for his marriage to Peronella of Aragon, which united the Kingdom of Aragon and the County of Barcelona as the Crown of Aragon and laid the foundations for the Catalano-Aragonese empire.
Ramon Berenguer IV actually became Prince Regent of Aragon after signing an agreement with Ramiro III of Aragon on August 11th 1137, when he was 24 and Peronella was just a year old.
The couple finally married in 1150, when Peronella was 14, and the couple had 5 children, including the future Alfons I of Aragon and Barcelona.
Throughout his lifetime he was officially "Count of the Barcelonans and Prince of the Aragonians" (Comes Barcinonensis et Princeps Aragonensis), rather than King.
He also extended the Lenguadoc domains through the acquisition of Bearn and Bigorra and also took Lleida and Tortosa from the Moors, and occasionally used the titles of "Marquis of Lleida and Tortosa".
You can read more about the union in the chapter Confusing the Kingdom with the Crown of Aragon from my book Catalonia Is Not Spain: A Historical Perspective.