A multi brick wall that is saved in height of 11 meters, in the south-east of the Theatre belongs to the Roman Thermes of Argos, a large public bath complex.

In this area, it should pre-exist during the 2nd century B.C. a sanctuary that was dedicated to Serapis, an Egyptian deity. His worship was introduced in the Hellenic land in 280 B.C. by Ptolemy I Soter, one of the successors of Alexander the Great, in an attempt to arrive at a compromise of the Greek and Egyptian religious perceptions. In this chthonic deity was digested more ancient Greek and Egyptian gods, like Pluto, Asclepius, Zeus Ammon, and the Nile.

In 100 A.D. the Serapeion had the form of a large columned courtyard. Along its western side, three rooms (B1, B2, and B3) were leading to a large room (A) that was ending in an arch. In the interior of room A existed a crypt, that was connected with an underground corridor and it contained three porous sarcophagi.

During the reign of Emperor Hadrian (117-136 A.D.) a complex of baths was installed in this area. The complex was under the auspices of Asclepius, the worship of whom progressively replaced that of Serapis. The Asclepeion is also mentioned by the traveler Pausanias who visited Argos during the 2nd century A.D.

In the Roman imperial times (2nd-3rd century A.D.) the sanctuary is changed into Thermes, a public bath complex that occupies the gallery and the columned courtyard, while the western rooms are maintained. The large room (A) with the impressive arches of its roof was used as a place for public gatherings and socializing (basilica thermarum). Through the central room (BI) the visitors were led to an oblong room with a perimetric mudbrick bench (D) that was used rather as vestiary. From this area and through two symmetrical rooms (E1 and E2) was done the entry in the room of the cold bath F (frigidarium). Ducts led the run-out waters from the bath-tubes to gutters under the floor. The semicircular and rectangular niches in the walls were decorated by statues, while the bath-tubes were bordered by columns from green marble with white Corinthian capitals. A small room (H) it followed that was used initially as auxiliary space or lavatory and later was changed into a bath. From the last unheated room (G) became the dispersion of the visitors in the hot bath rooms (C1, C2, and C3), with two or three bath tubes. Under its floors existed the hypocausts, mudbrick little columns, which allowed the circulation of the hot air. The building was framed by Palaestra in the west and by a monumental staircase in the east.

The bath complex functioned until the Early Christian times (5th - 6th century A.D.). Its monumental upper part was remained visible after its abandonment and was depicted by the travelers along with the seats of the Theatre. The excavations of the French Archaeological School that began in the 1950’s revealed the building complex and numerous mobile finds.

Argo’s Thermes belong in the public bath complexes of a monumental scale of the Roman times that constituted a place of meeting, socializing, exercise, and recreation of the citizens. Their luxury is testified by the elaborate mosaics and the marble floors but mainly by the great number of statues that had been set up in the rooms’ niches and they depicted gods and heroes.”