This rectangular palace built in the 17th century is now the headquarters of the Ministry for Foreign Affairs, European Union and Cooperation, and has been since 1938. In 1996, it was declared a Site of Cultural Interest. 

The palace is made up of two buildings from different periods, joined by an interior courtyard and two overhead walkways. Phillip IV ordered the construction of the main building as a  Court Jail  and Mayors’ Hall, which was built between 1629 and 1736 and designed by Juan Gómez de Mora, who was helped in the works by Cristóbal de Aguilera. It has a rectangular and symmetrical layout around two square courtyards with three entrances on its main front. The hall, the large staircase and the chapel stand out, which is now an area for transit. The façade is symmetrical with a marked horizontality broken by the angular towers topped with spires. The main front has three openings overlapped with bodies and is finished with an attic which houses the royal crest.  

In 1791, it was destroyed by fire in which only the façade was left standing, and it was Juan de Villanueva who was responsible for its reconstruction, between 1792 and 1793. In 1786, the Convent of Salvador was bought to extend the facilities and adaptation work began under the supervision of Mateo Güill and Bautista Sánchez. It was used as a jail until 1846, when it was knocked down and the land was sold. 

A century later, Pedro Muguruza came up with the project for the extension of the Ministry of Foreign Affairs, remodelling the main building, which was carried out after the Civil War.