"forced to convert or be expelled"
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).
Along with the desire of the Catholic Monarchs to extend their dominion to all the kingdoms of the Iberian Peninsula, their reign was characterized by religious unification around Catholicism. Pope Innocent VIII granted the Catholic Kings the right of Patronage over Granada and the Canary Islands, which meant the control of the state in religious affairs. A bull of Pope Sixtus IV, in 1478, created the Inquisition in Castile for a control of the purity of the faith. Since Aragon existed since 1248, in this way the Spanish Inquisition was the only common institution for the two kingdoms. The stage of Fray Tomás de Torquemada as Inquisitor General was very hard.
In 1492 the Kings decreed the forced conversion to Christianity of the Jews of their kingdoms - calling them "marranos" - and the expulsion or execution of those who refused. Ten years later they also forced the Muslims to convert to Christianity - calling themselves "Moriscos" - or to leave Spain. They also instituted a permanent embassy to the Holy See.
