The site of the marriage of Carlos V and Isabel of Portugal.

Peter I, the Cruel, rebuilt the old Almohad fortress and made it into his royal residence. It suffered serious deterioration with time and had to be refurbished during the reign of Isabel II.

The interior of the building is arranged around two courtyards: the courtyard of Las Doncellas, where official life took place, or the Las Muñecas courtyard, for private life. The Ambassadors' Hall is beautifully decorated with plasterwork and tiles. The top floor is accessed by a 16th-century coffered staircase decorated with paintings by Roelas and Madrazo. Highlights include the furniture and the tapestries that decorate the different rooms.