The Aragonese Crown was a historical political entity that emerged in the late Middle Ages, primarily centered in the Kingdom of Aragon. It played a significant role in the formation of the Crown of Aragon, which included territories such as Catalonia, Valencia, and the Balearic Islands. The crown was known for its unique system of governance, which allowed for a degree of autonomy in its various regions. The Aragonese Crown was influential in the Mediterranean, engaging in trade and military campaigns. It also participated in the Reconquista, the effort to reclaim the Iberian Peninsula from Muslim rule. The union of the Crown of Aragon with the Crown of Castile in the late 15th century marked the beginning of modern Spain.