The Catholic monarchs (Spanish: Reyes Católicos) is the collective title used in history for Queen Isabella I of Castile and King Ferdinand II of Aragon. They married in 1469, uniting both crowns and creating the kingdom of Spain. The nickname refers to the extreme catholic views they shared, which led them to expel the Moors from the Iberian Peninsula with the conquest of Granada and to force the conversion of thousands of Jews. The Inquisition was created by their royal decree.
Their joint motto was Tanto monta, monta tanto ("It amounts so, so it amounts"). It was created by Antonio de Nebrija and was either:
- an allusion to the Gordian knot: Tanto monta, monta tanto, cortar como desatar ("..., cutting as untying")
- explaining the equal footing for both monarchs: Tanto monta, monta tanto, Isabel como Fernando ("..., Isabella as Ferdinand")