Hutton Webster, Early European History
“ UNION OF CASTILE AND ARAGON, 1479 A.D. Meanwhile the separate Spanish kingdoms were coming together to form a nation. León and Castile in 1230 A.D. combined into the one kingdom of Castile, so named because its frontiers bristled with castles against the Moors. But the most important step in the making of Spain was the marriage of Ferdinand of Aragon to Isabella of Castile, leading in 1479 A.D. to the union of these two kingdoms. ”
