Joanna (6 November 1479 – 12 April 1555), known as Joanna the Mad , was queen of Castile from 1504 and of Aragon from 1516. From the union of these two crowns modern Spain evolved. Joanna married Philip the Handsome on October 20, 1496. Philip was crowned King of Castile in 1506, initiating the rule of the Habsburgs in Spain. After Philip's death that same year, Joanna was deemed mentally ill and was confined to a nunnery for the rest of her life. Though she remained the legal queen of Castile throughout this time, her father, Ferdinand II of Aragon, was regent until his death, when she inherited his kingdom as well. From 1517, her son, Charles, ruled as king, while she nominally remained co-monarch.