Isabella I of Castile and Ferdinand II of Aragon were Catholic monarchs who united their kingdoms through marriage in 1469 and supported Christopher Columbus's voyage to Asia in 1492. Isabella inherited the throne of Castile in 1474 and fought disputes over succession, while Ferdinand received the throne of Aragon in 1479 after the death of his father. Together they participated in struggles for Isabella and established a dynastic union between Aragon and Castile, beginning their joint reign through agreements maintaining equality.