Joanna of Castille at the funeral of her husband (oil on canvas)

Joanna (6 November 1479 – 12 April 1555), known as Joanna the Mad (Spanish: Juana la Loca), was heiress of the Kingdoms of Castile and Aragon, a union which evolved into modern Spain. She married Philip the Handsome, initiating the rule of the Habsburgs in Spain. After her mother's death, the couple briefly ruled Castille (1504-1506). After Philipp's death in 1506, Joanna became mentally ill and was confined to a nunnery for the rest of her life. Though legally queen of Spain throughout this time, her father Ferdinand and later her son Charles ruled in her place.