Katharine of Aragón, 1485–1536, first queen consort of Henry VIII of England; daughter of Ferdinand II of Aragón and Isabella of Castile. In 1501 she was married to Arthur, eldest son of Henry VII. He died in 1502, and the marriage of Katharine to his brother, Henry, was projected. A papal dispensation was obtained, but the marriage was delayed by diplomatic wrangling between Henry VII and Ferdinand and did not take place until the prince had ascended (1509) the throne as Henry VIII. As governor of the realm during Henry's expedition to the Continent in 1513, she organized the successful defense against Scottish invasion that ended in the English victory at Flodden. Only one of Katharine's six children survived infancy (see Mary I), and Henry was disappointed at her failure to produce a male heir. The English alliance with Katharine's nephew, Holy Roman Emperor Charles V, wavered and fell in 1525, and her political importance declined. Finally, Henry became strongly infatuated with Anne Boleyn. In 1527, with the help of Cardinal Thomas Wolsey, Henry began the attempt to have his marriage annulled. This move precipitated the chain of events that ended in the English Reformation. Katharine steadfastly refused to acknowledge the invalidity of the marriage or to retire to a convent. In 1529 at a trial conducted by cardinals Campeggio and Wolsey, she appealed vainly to Henry, denied the jurisdiction of the court because it was under pressure by the king, and withdrew. Pope Clement VII, a virtual prisoner in Rome of Charles V, recalled the hearing to Rome, in effect denying the divorce. Henry then proceeded on his own; after his secret marriage to Anne Boleyn in 1533, a court presided over by Thomas Cranmer pronounced the former marriage invalid. Katharine refused to accept the decision. The pope's formal declaration for her in 1534 came too late. She was separated from her daughter, Mary, never visited by Henry, and confined with few attendants at various inferior estates. Katharine nevertheless refused, despite all threats and mistreatment, to take the title of princess dowager or to acknowledge the Act of Succession and the Act of Supremacy. Her great popularity with the common people of England never waned throughout the long period of her misfortunes. She died after a prolonged illness.

See biographies by G. Mattingly (1941, repr. 1960), M. M. Luke (1967), and G. Tremlett (2010); A. Du Boys, Catherine of Aragon and the Sources of the English Reformation (1881, repr. 2010).