Isabella I of Castile

Isabella I of Castile, known to later generations as Isabella the Catholic, was born in 1451 at Madrigal de las Altas Torres in the Kingdom of Castile. She was the daughter of King John II of Castile and his second wife, Isabella of Portugal, and a member of the Trastámara dynasty. Her father died when she was a small child, and she grew up during the weak and contested reign of her half-brother Henry IV. Court factions, noble revolts, and uncertainty over the succession shaped her youth. She was educated in a manner befitting a princess of her time, with particular emphasis on religion, and she developed a reputation for personal piety, determination, and political caution. For a period she lived under constraint at court or in assigned residences, as Henry IV sought to control her marriage and her potential claim to the throne.

The decisive event of her early adulthood was her marriage in 1469 to Ferdinand, son of John II of Aragon. The wedding, celebrated at Valladolid, was contracted against the preferences of Henry IV, who had considered other alliances, including a Portuguese match. When Henry died in 1474, Isabella had herself proclaimed queen of Castile at Segovia, asserting her right over that of Joanna, Henry's putative daughter, whose legitimacy many Castilian nobles denied. The resulting War of the Castilian Succession drew in Afonso V of Portugal, who married Joanna and invaded Castile. After years of fighting, Isabella and Ferdinand secured their position; the Treaty of Alcáçovas in 1479 recognized Isabella as queen of Castile and also settled Atlantic spheres of influence with Portugal. In the same year Ferdinand inherited Aragon. The two sovereigns ruled their respective realms in tandem, coordinating policy while preserving the separate laws and institutions of Castile and Aragon. Pope Alexander VI later conferred on them the title of Catholic Monarchs.

Isabella's government in Castile worked to restore royal authority after decades of disorder. She and Ferdinand reorganized the royal council, used the Santa Hermandad as an instrument of public order, and asserted control over military orders and high appointments. Religious policy was central to her conception of monarchy. With papal authorization they established the Spanish Inquisition in Castile in the late 1470s, intended to investigate conversos suspected of secretly practicing Judaism. In 1492, after the long Granada War, the last Muslim kingdom in Iberia surrendered; Isabella and Ferdinand entered Granada, completing the Reconquista. That year they also issued the edict requiring Jews in their kingdoms to convert or leave, a measure that ended centuries of open Jewish presence in Spain and sent many into exile. Isabella authorized the voyage of Christopher Columbus in 1492, which led to Castilian claims in the Caribbean and, over the following years, to a rapidly expanding overseas empire. She took an interest in the legal status and conversion of indigenous peoples, issuing instructions that mixed evangelizing aims with the realities of conquest and settlement.

The royal couple had five children who survived infancy: Isabella, who married into the Portuguese royal house; John, Prince of Asturias, whose early death was a dynastic blow; Joanna, who married Philip the Handsome of Burgundy and later inherited Castile; Maria, who became queen of Portugal; and Catherine, who married Arthur, Prince of Wales, and then Henry VIII of England. The deaths of John and of the eldest daughter Isabella, and the death of a Portuguese grandson, left Joanna as heiress, a prospect that troubled Isabella because of Joanna's mental state and the influence of her Habsburg husband. Isabella died in 1504 at Medina del Campo, having dictated a will that sought to protect Castilian interests and the succession. She was buried in Granada, in the Royal Chapel built to hold the remains of the Catholic Monarchs. Her historical image remains dual: architect of a powerful, confessional Spanish monarchy and sponsor of a world-changing encounter with the Americas, and also a ruler whose drive for religious unity entailed the Inquisition and the expulsion of Jews. Although a process for her beatification has been advanced in the Catholic Church, she has not been beatified or canonized.