The Alhambra was so called because of its reddish walls (in Arabic, («qa'lat al-Hamra'» means Red Castle). It is located on a strategic point, with a view over the whole city and the meadow (la Vega), and this fact leads to believe that other buildings were already on that site before the Muslims arrived. The complex is surrounded by ramparts and has an irregular shape.

The castle of the Alhambra was added to the city's area within the ramparts in the 9th century, which implied that the castle became a military fortress with a view over the whole city. In spite of this, it was not until the arrival of the first king of the Nasrid dynasty, Mohammed ben Al-Hamar, that the royal residence was established in the Alhambra. This event marked the beginning of the Alhambra's most glorious period.