Joan (Nov/6/1479 –Apr/12/1555), known as Joan the Mad (Spanish: Juana la Loca), was the heiress of the Kingdoms of Castile and Aragon, a union which evolved to become modern Spain. She married Philip the Handsome, initiating the rule of the Habsburgs in Spain. After her mother’s death, the couple briefly ruled Castilla from 1504 to 1506. After Philip’s death in 1506, Joanna became mentally ill and was confined to a nunnery for the rest of her life. Though she remained the legal queen of Spain throughout this time, her father Ferdinand and later her son Charles ruled in her place.
Her mother Isabella I of Castilla, financed the journey of Christopher Columbus with her own money, apparently a bad investment, eventuality it would pay off after Columbus discovered America and Spain claimed most of the continent as it’s colony.
Her son Charles would become the Emperor of most of Europe (Spain, Holy Roman Empire and parts of Italy and Portugal), besides he would be the king of all the new territories claimed by Spain in America. Her other children would become the kings and queens of Europe, Despite that, she spent most of her life sad, deprived of her liberty inside the nunnery.