The Catholic Kings was the denomination that received the spouses Fernando II of Aragon and Isabel I of Castile, sovereigns of the Crown of Castile (1474-1504) and the Crown of Aragon (1479-1516).
1 - With their marriage bond they were united, in the dynasty of the Trastámara, two crowns, the Crown of Castile and the Crown of Aragon giving birth to the Hispanic Monarchy.
2 - They established a strong monarchy against the power desires of ecclesiastics and nobles. This dynastic union was characterized by the fact that the sovereignties, norms and institutions of each kingdom and crown were maintained.
3 - The successful expansionist foreign policy carried out by Ferdinand and Isabella was possible thanks to a series of factors: King Fernando's diplomatic initiative continued the traditional policy of the Crown of Aragon, with its interests set in the Mediterranean Sea and in rivalry with France , which however had never been an enemy of Castile, we also see that the diplomacy of the kingdom of Castile was oriented mainly towards the Atlantic Ocean and its overseas expansion towards the New World, America.
4 - Once Isabel and Fernando were confirmed on the throne of Castile, they resumed the conquest of the Nasrid Kingdom of Granada, the last Muslim stronghold of the Iberian Peninsula, expelling the Muslims from all over the kingdom.
