It was built in the 14th century to serve as a gateway and tower of the walls which surrounded the city. It was rebuilt in the 16th century by Juan de Vallejo and Francisco de Colonia in the form of a triumphal arch. It features Emperor Charles V surrounded by the most significant personages of the history of the city and of Castile. It is noted for the Sala de Poridad, which was the hall where the Council of Burgos met until the 18th century, with its El Cid motifs and Mudejar coffered ceiling. Its Main Hall contains a painting by Vela Zanetti, remains of Mudejar plasterwork, and the pharmacy of the former Hospital de San Juan.