This thermal baths building, called thus as it was the first to be investigated in the Tharros area, stood overlooking the Gulf of Oristano coastline, on the northeast edge of the public area of the city (figs. 1-2).

Fig. 1 - Location of the Thermal baths nr. 1 (from Google Earth. Review C. Tronchetti)

Fig. 2 - Thermal baths nr. 1 (photo by Unicity S.p.A.)

Unfortunately erosion by the sea and several renovations, changes and plundering that the building underwent over the centuries on the other has made it rather difficult to interpret, especially due to the largely missing wall elevations (fig. 3).

Fig. 3 - Map of the Thermal baths nr. 1: 1) changing room; 2) calidarium; 3) calidarium (from ZUCCA 1984, p. 88)

The thermal baths were entered from the road, into the changing room (apodyterium), which then led into the large frigidarium, which no longer exists but which would have been in the northern part of the building, where the large water cisterns used for filling the baths were located.

Two hot rooms are adjacent to the changing room on the eastern side, that can be identified by the paving that, during the excavation, still had part of the suspensurae that supported the floor, allowing the passage of hot air through the cavity.

The floor paving in terracotta slabs still contained stamps with the names of the manufacturers: IULIANI ET QUAD(rati), local manufacturers known from other findings in the Tharros area. The thermal baths are thought to have been built in the 2nd century A.D. (figs. 4-8).

Fig. 4 - Thermal baths nr. 1 from the south (photo by Unicity S.p.A.)

Fig. 5 - The large cistern for the Thermal baths nr. 1 (photo by Unicity S.p.A.)

Fig. 6 - The northern calidarium transformed into a cemetery (photo by Unicity S.p.A.)

Fig. 7 - The entrance to the northern calidarium opened in the Vandal era (photo by Unicity S.p.A.)

Fig. 8 - Remains of a praefurnium (photo by Unicity S.p.A.)

The thermal spa building, in particular the calidarium indicated with the number 3 on the map, underwent heavy renovation and change, aimed at a different type of use. The building was partly used as a cemetery in the Vandal and Byzantine eras (fig. 7), and was partly connected with a Paleo-Christian place of worship that was built north of the Thermal baths.