Catholic monarchs or in Spanish “Reyes Católicos” was the collective title used in history for Queen Isabella I of Castile and King Ferdinand II of Aragon. Isabella and Ferdinand married in 1469. This marriage was uniting both crowns (Aragon and Castile) and created the kingdom of Spain. The nickname “Catholic Monarchs” refers to the extreme catholic views that Isabella and Ferdinand 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. The title was bestowed on them by Pope Alexander VI.
Their joint motto was Tanto monta, monta tanto ("It amounts so, so it amounts"). Their symbol was el yugo y las flechas, a yoke and a fasces of arrows. The yoke is another allusion to the Gordian knot. Y and F are the initials of Ysabel (archaic spelling) and Fernando. This symbol was later used by the Spanish fascist party the Falange, which claimed the glory and the ideals of the Reyes Católicos.