King Alfonso II of Aragon, born in 1152, was a significant medieval ruler known for his contributions to the Crown of Aragon. He became king in 1162 and played a crucial role in expanding his kingdom through military campaigns and strategic marriages. His reign marked the beginning of the Aragonese expansion into Catalonia and Valencia. Alfonso II was also notable for his support of the Catholic Church and the establishment of legal codes. He was the first king to adopt the title of "King of Aragon" and is remembered for his efforts in unifying the region, which laid the groundwork for future Aragonese monarchs.