The Patio de la Reja was built between 1654 and 1655 to serve as the courtyard for the Habitaciones Imperiales (Emperor's Chambers)
, which were a set of rooms intended for Emperor Charles V. The courtyard is named after the wrought iron grille balcony that runs along the top of its southern wall.
The Alhambra and the Generalife: Official Guide
. Madrid: Patronato de la Alhambra y Generalife and Tf Editores, 2010.