Inaugurated in 1889, Crypta Balbi is part of the Museo Nazionale Romano, together with Palazzo Massimo alle Terme, Palazzo Altemps e Terme di Diocleziano.
The Crypta Balbi Museum is housed in a complex between Via delle Botteghe Oscure and Via Castani which includes two houses of medieval origin on Via Botteghe Oscure and the "Barberini dormitory" on Via Caetani. The design of the layout and the routes of access provide the viewer with the opportunity to see the articulation of the ancient buildings and the original communication routes in an area that has had a substantial continuity of life from Roman times to the present day.
The archaeological excavation and the restoration project of such an important complex, which can be considered one of the most successful projects of urban archeology, has been conducted for twenty years or so since the 1980s, and has allowed us to understand the various building phases of the area. In Roman times, the area was occupied by a large colonnaded courtyard annexed to the theater of Balbus that was erected in 13 BC and later transformed and adapted in later times, especially during the Medieval and Renaissance periods with the establishment of the Monastery of Santa Maria Domine Rose created in the eighth century, the merchants' houses built after 1000 against the wall of the Crypt, and the Conservatory of Santa Caterina dei Funari built in the 16th century.
The theatre was built by L. Cornelius Balbus the Younger in the year 13 AD, behind the Portico d’Ottavia in the heart of the current Jewish quarter. The theatre of Balbus was the third theatrical building in the Campo Marzio, and is proof of how the Greek culture and the fashion of theatrical performances was already very popular by the second half of the I century before Christ. The ruins of the cavea of the theatre are located under the Mattei Paganica Palace, in the area behind the church of S. Caterina deiFunari and in the cellars of the Mattei di Giove Palace. Another excavation, visible in via Michelangelo Caetani, has allowed locating the ruins of the portico in front of the stage, closed by an exedra of pillars, as also shown in a fragment of Forma Urbis, the ancient marble map of the city. The fragment shows the name of the quadriportico, Crypta Balbi, that must have also included at its center a small temple perhaps dedicated to Vulcan. In the Middle Ages the rooms of the theatre hosted the workshops of craftsmen that produced lime, ropes and glass articles.