Ferdinand II, called the Catholic, was King of Sicily from 1468 and King of Aragon from 1479 until his death. The 1469 marriage of Ferdinand, heir apparent to the crown of Aragon, and Isabella of Castile, heir apparent to the crown of Castile, was the marital and political "cornerstone in the foundation of the Spanish monarchy." As a consequence of his marriage to Isabella I, he was de jure uxoris King of Castile as Ferdinand V from 1474 until her death in 1504. At Isabella's death the crown of Castile passed to their daughter Joanna, by the terms of their prenuptial agreement and her last will and testament. Following the death of Joanna's husband Philip I of Spain, and her alleged mental illness, Ferdinand was recognized as regent of Castile from 1508 until his own death. In 1504, after a war with France, he became King of Naples as Ferdinand III, reuniting Naples with Sicily permanently and for the first time since 1458. In 1512, he became King of Navarre by conquest. In 1506 he married Germaine of Foix of France, but Ferdinand's only son and child of that marriage died soon after birth; had the child survived, the personal union of the crowns of Aragon and Castile would have ceased.