The design of the Barracks for Invalids and Volunteers on Horseback dates from 1774 and experts coincide in attributing it to Juan de Villanueva. Since its construction, the original architectural characteristics have remained mostly unchanged, with some slight alterations.
The building floor shape is rectangular, and originally was separate from the surrounding buildings, although today it adjoins the market. On the outside, it echoes the Monastery and the Houses of Trades, with very smooth walls of granite masonry, cornices of the same material and sloped slate roofs. Of note inside the building are the staircase and the predominance of vaulted spaces.
Shortly after building had finished, in addition to its use as a barracks, it functioned simultaneously as a prison. From 1887, its function was limited to that of prison. In 1972, the Town Council assigned the building to the Social Security Agency (Tesorería General de la Seguridad Social) and a centre for retired people ("Hogar del Pensionista") was set up. Subsequently the building was restored, treating its structure with great respect.
There is currently a project in existence to convert it into the headquarters of the Centre of Herreran Studies, for which the legacy of Mr. Luis Cervera Vera will be used.