Ferdinand V (1452-1516), or Ferdinand the Catholic, and his wife, Isabella I, were joint sovereigns of Castile. As Ferdinand II, he was king of Aragon. He laid the foundations of Spanish unity and imperial power.

Born on March 10, 1452, at Sos, in Aragon, Ferdinand was the son of John II of Aragon and Juana Enriquez of Castile. In 1469 he married Isabella, heiress apparent to the Castilian crown. They became joint monarchs of Castile on the death of her brother Henry IV in 1474. In 1479 John II died, and Ferdinand became king of Aragon as well as of Castile (in whose government, however, he officially occupied second place).

Domestic Policy

In the union of crowns thus achieved, Castile's growing wealth and larger population gave it predominance. At the same time the lands of the two crowns retained their separate constitutional identities; and while the Catholic Monarchs might achieve a measure of...