The site where the Military Government building now stands was once the palace of the Marquises of Montaos, which was built in 1520 and donated to the Royal Treasury in 1640. At the beginning of the 18th century, the Galician Army Overseer's Office and Accountant's Office was installed here, which would later give its name to the street of the main façade. This was a body integrated in the Army Quartermaster's Office in charge of economic supervision, auditing of accounts, fraud control, etc. During the same century, it was the temporary home of two General Captains of Galicia, notably Carlos Francisco de Croix, but above all it served as the residence of the Quartermasters General of the Kingdom of Galicia. In 1875, the Civil Government occupied the building. A short while after, the Military Government was installed here, remaining in the hands of the army until 2009.
The current building was renovated in 1758 by the military engineer Antonio Gaver, although it subsequently underwent several redevelopments to adapt it to its later uses. It is a typical eighteenth-century palace with a baroque façade, crowned with a coat of arms and with small balconies with French-style visors. Today, the west wing of the building is the headquarters of the Cidade Vella Civic Centre.