Granary or frumentari monti had been established under Spanish administration in the first half of the 17th century. In Marmilla they had sprung up by ecclesial initiative, with primarily welfare purposes. The Monte Granatico in Villamar, located on the corner of Via Indipendenza and Via Cagliari, is divided into four bodies, covering an area of about 810 square meters and enclosing a patio of about 200 square meters. Until the 1990s it housed the local Banco di Sardegna agency. Restorations in the early 2000s made a room open to the inner courtyard with an entrance from Via Indipendenza usable.
The hall has a large exhibition space from which there is access to a space above of equal shape and extent. The remaining bodies have not yet undergone restoration. The structure is intended to house the archaeological museum.