On the site of Pope Sixtus V's Villa Montalto-Peretti (demolished in 1883 after the construction of the nearby train station), the present building was constructed in the neo-cinquecentesco style between 1883 and 1887 by the architect Camillo Pistrucci to house a Jesuit seminary. Used partially as a military hospital during the second world war, it then returned to scholastic functions until 1960. In 1981, by which time it was crumbling, the State acquired it for 19 billion lire and granted it to the museum. Its restoration and adaptation began in 1983. It was inaugurated as part of the museum in 1995 and completed in 1998. 

 

The museum hosts sculptures, frescoes and mosaics, coins and jewels document the evolution of the Roman artistic culture from the late Republican age through Late Antiquity (2nd c. BCE - 5th c. CE) along an exhibition path in which Ancient Roman history, myths and everyday life live anew.

In the rooms of the ground floor are exhibited splendid Greek originals discovered in Rome such as the Boxer at Rest, the Hellenistic Prince and the Dying Niobid from the Horti Sallustiani [Gardens of Sallust] as well as portraiture of the Republican and Imperial ages, culminating in the statue of Augustus Pontifex Maximus (High Priest).

On the first floor are displayed celebrated masterpieces of statuary, among them being the Lancellotti Discobolus (Discus Thrower), the Maiden of Antium and the Hermaphroditus Asleep, as well as magnificent sarcophagi such as the Sarcophagus of Portonaccio, with a battle scene carved in high relief.

On the second floor, frescoed walls and pavement mosaics document the domestic decor of prestigious Roman dwellings.

The basement houses the sizeable numismatic collection, besides grave ornaments, jewels and the Grottarossa Mummy.

 

(source: wikipedia and http://archeoroma.beniculturali.it/en/museums/national-roman-museum-palazzo-massimo-alle-terme)