The Aragonese Monarchy refers to the royal lineage that ruled the Kingdom of Aragon in northeastern Spain. Established in the early Middle Ages, it became a significant political power in the region, especially during the 12th to 15th centuries. The monarchy played a crucial role in the Reconquista, the effort to reclaim the Iberian Peninsula from Muslim rule, and expanded its influence through strategic marriages and alliances. The Aragonese Monarchy is notable for its union with the Crown of Castile through the marriage of Ferdinand II of Aragon and Isabella I of Castile in 1469. This union laid the foundation for the modern state of Spain. The monarchy's legacy includes the promotion of Catalan culture and the establishment of a unique legal system known as the Fueros.