King James I of Aragon was a significant medieval ruler who reigned from 1213 to 1276. He is best known for his conquests in the Iberian Peninsula, particularly the capture of Valencia from the Moors in 1238. His reign marked the expansion of the Crown of Aragon and the establishment of a more centralized government. James I was also a patron of the arts and culture, promoting the use of the Catalan language. He is credited with the compilation of the Llibre dels fets, an autobiography that provides insight into his life and reign. His legacy includes the strengthening of Aragon's influence in the Mediterranean.