Isabella I of Castile

Isabella I of Castile, renowned as 'Isabella the Catholic' (Isabel la Católica), was one of the most powerful, influential, and formidable female sovereigns in European history. Securing the crown of Castile in 1474 following civil war, her secret 1469 marriage to Ferdinand of Aragon laid the political foundation for the unified Kingdom of Spain.

Isabella's reign changed the course of world history in a single momentous year: 1492. In January 1492, she and Ferdinand personally entered the Alhambra, receiving the surrender of Muhammad XII of Granada and completing the seven-century Reconquista of the Iberian Peninsula from Muslim rule. Months later in Santa Fe, Isabella agreed to sponsor Christopher Columbus's transatlantic voyage of exploration, which discovered the Americas and laid the foundations of the global Spanish Empire. Isabella established the Spanish Inquisition and reformed civil law, while dictating in her will that the indigenous peoples of the New World must be treated as free subjects of the Crown.