This building was erected in the 16th century by Juan de Contreras. It owes its name to Francisco Colmenares, Count of Polentinos. The façade is Plateresque, rebuilt in the 20th century. It has a remarkable portal, made by the sculptor Vasco de la Zarza. Inside we find a beautiful arcaded courtyard, with columns arranged in two levels. The top storey is lined by a balustrade and glass windows. It is presently the site of the General Military Archives.