James I of Aragon, also known as James the Conqueror, was a significant medieval king who ruled from 1213 to 1276. He was born in 1208 and became king at a young age after the death of his father, Peter II of Aragon. James is best known for his military campaigns that expanded the Crown of Aragon into Valencia and the Balearic Islands. During his reign, James I established a strong administrative system and promoted the use of the Catalan language. He also played a crucial role in the Reconquista, the effort to reclaim territory from Muslim rule in the Iberian Peninsula. His legacy includes the unification of various regions under Aragonese control.