Joanna of Castile

Joanna was the daughter of Isabella I of Castile and Ferdinand II of Aragon, married by arrangement to Philip the Handsome in 1496. A series of deaths between 1497 and 1500 - her brother, her sister, her nephew - made her heir to both kingdoms. When her mother died in 1504, Joanna became queen of Castile, though her father immediately proclaimed himself governor. In 1506 her husband briefly claimed the throne as Philip I, initiating Habsburg rule, then died within months. Despite being the ruling queen, Joanna was declared insane and confined to the Royal Palace in Tordesillas under her father's orders; he ruled as regent until 1516, when she inherited Aragon as well. Her son Charles I took the throne, and Joanna remained locked away, nominally co-monarch, for the rest of her life. She died in confinement in 1555 at seventy-five, her madness still debated by historians as either genuine or a convenient pretext.