The Alcázar de los Reyes Cristianos (Spanish for "Castle of the Christian Monarchs"), also known as the Alcázar of Córdoba, is a medieval Alcázar located in the historic centre of Córdoba, Spain, next to the Guadalquivir River and near the Grand Mosque. The Alcázar takes its name (Arabic: القصر, translit. Al-Qasr, lit. 'The Palace'). The fortress served as one of the primary residences of Isabella I of Castile and Ferdinand II of Aragon.