The queen of Castile, Joanna of Castile, married this member of the house of Habsburg who was the son of which monarch?
Joanna of Castile Joanna (6 November 1479 – 12 April 1555), called the Mad (Spanish: "Juana la Loca" ), 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 20 October 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 1516, her son, Charles I, ruled as king, while she nominally remained co-monarch.
Isabella of Navarre, Countess of Armagnac Isabella of Navarre (1395 – 31 August 1450) was the younger surviving daughter of Charles III of Navarre and his wife Eleanor of Castile. She was a member of the House of Évreux.