Isabella I | Biography, Reign, & Facts | Britannica
Isabella I, byname Isabella the Catholic, Spanish Isabel la Católica, (born April 22, 1451, Madrigal de las Altas Torres, Castile—died November 26, 1504, Medina del Campo, Spain), queen of Castile (1474–1504) and of Aragon (1479–1504), ruling the two kingdoms jointly from 1479 with her husband, Ferdinand II of Aragon (Ferdinand V of Castile). Their rule effected the permanent union of Spain and the beginning of an overseas empire in the New World, led by Christopher Columbus under Isabella’s sponsorship.
Isabella was the daughter of John II of Castile and his second wife, Isabella of Portugal. Three years after her birth