The Granada War was a series of military campaigns between 1482 and 1492 during the reign of the Catholic Monarchs, Isabella I of Castile and Ferdinand II of Aragon, against the Nasrid dynasty's Emirate of Granada. It ended with the defeat of Granada and its annexation by Castile, ending the last remnant of Islamic rule on the Iberian peninsula.

The Catholic Monarchs were Queen Isabella I of Castile and King Ferdinand II of Aragon, whose marriage and joint rule marked the de facto unification of Spain. They were both from the House of Trastámara and were second cousins, being both descended from John I of Castile; to remove the obstacle that this consanguinity would otherwise have posed to their marriage under canon law, they were given a papal dispensation by Sixtus IV. They married on October 19, 1469, in the city of Valladolid; Isabella was 18 years old and Ferdinand a year younger. It is generally accepted by most scholars that the unification of Spain can essentially be traced back to the marriage of Ferdinand and Isabella. Their reign was called by W.H. Prescott "the most glorious epoch in the annals of Spain".