The Kings of Aragon were the rulers of the Kingdom of Aragon, which emerged in the early Middle Ages in what is now northeastern Spain. The kingdom played a significant role in the Reconquista, the centuries-long effort to reclaim the Iberian Peninsula from Muslim rule. The monarchy expanded its influence through strategic marriages and military conquests, eventually forming a union with the Kingdom of Navarre and later the Crown of Aragon. One of the most notable kings was James I of Aragon, who reigned from 1213 to 1276. He is known for his conquests in Valencia and Mallorca, which significantly expanded the kingdom's territory. The Crown of Aragon later became a powerful maritime empire, influencing trade and politics in the Mediterranean region.