16. King Ferdinand and Queen Isabella vs. Joanna the Mad
King Ferdinand II of Aragon and Queen Isabella I of Castile’s daughter, Joanna, known as “the Mad,” faced a contentious relationship over her capacity to rule. After Isabella’s death in 1504, Joanna ascended to the Castilian throne, but Ferdinand and her husband, Philip the Handsome, questioned her mental stability. In 1506, Ferdinand and Philip signed the Treaty of Villafáfila, effectively removing Joanna from power and allowing Philip to govern Castile. Joanna was confined to the Royal Convent of Santa Clara in Tordesillas, where she remained until her death in 1555. (en.wikipedia.org)
