Excavations undertaken from 1993 onwards on the ancient bath complex of Mezzomiglio, in the centre of Chianciano Terme, uncovered a site which may have been a cult centre for individuals who practised an ascetic lifestyle, believing in the power of water. This centre was at its height between the 1st and 2nd century A.D. declining in the 3rd century A.D., although the site continued in use until the 5th or early 6th century A.D. and was occasionally occupied during the medieval period.
At the end of the 1st century B.C. the baths at Chianciano were already famous. In fact, the poet Horace went there to be cured by these health giving waters on the advice of the doctor Antonius Musa who had cured the Emperor Augustus of a grave illness by using only cold baths and hot compresses.

The large sandstone blocks from the terracing relate to the first phase (datable to between the 2nd century B.C.- beginning of the 1st century B.C.). They may have been part of the upper city’s defences which itself may date to an earlier period, between the 4th and 2nd century B.C.

Fragments of 2nd century B.C. black glaze pottery belong to this phase and it is thought that a large pool with an internal facing of opus incertum, fed by spring water also dates to this phase. A podium for a sacellum or small temple, found on the west side of the pool seems to date to the beginning of the 2nd century B.C., however it is not clear whether the sacellum in its final form was built in this period. Considering the many construction phases and building techniques used it is possible that the pool remained in use for immersions at the centre of the health cult until the 2nd or 3rd century A.D. and was then used as a drinking trough for animals until the late 5th century A.D.
The pool was the characteristic feature of the area during the entire first phase, no traces of other structures or roads datable to before the late 1st century B.C. were found.

Two phases preceding that of the Trajanic period were identified: the first dating to the 1st century B.C., attested by a wall found to the north-east of the sacellum, the second, dating to between the end of the 1st century B.C. and the 1st century A.D., with traces of a glareatio east of the sacellum.

The pool took on a more refined form in the Trajanic period (the double sloped floor was made of terracotta imbrices, some with consular stamps of 114 A.D.) when the entire area was restructured. It is probable that the urban development desired by the owners of the spa sanctuary took place in this third phase and represented a clear change from the former more rural management.
The Trajanic baths were surrounded by four roads in a trapezoidal lay out which enclosed a sort of walkway around the bath building itself. The roads were contemporary with the cobbled courtyard and the roads in the central and eastern parts of the site. A new gravel road belonging to this phase was found which sloped down to the north-east, to the north of which were structures A and D of this period.

Structure A was conceived as a large room accessed via three wide steps through a large entrance to the west. It contained material of 1st century A.D. date, found in the fill of the pathway surrounding both this structure and structure D. Structure A was a rustic building, with a foundation of stones above which was a wooden superstructure with oak door jambs and sandy clay and wattle walls. The vertical jambs and the walls were supported by a structure of beams placed so as to form an A, covered with roof tiles. The investigations showed that structure A had an extra room inside, accessible only from the north side of the main room. It may be suggested that once an offering had been made at the entrance to the building, people gathered by the statue of the divinity in the main room (where a masonry footing, perhaps a statue base was found). Here they waited to be admitted into this small room (5m2) which contained a small water channel running from west to east, covered by a limestone slab. It is probable that this room, rather than functioning as a latrine (as first thought), was used for ritual ablutions.

During the 3rd century the site began to fall into ruin. Rough repairs undertaken on the north wall of the pool suggest that there were problems with leaks. In circa 360 A.D. a fire destroyed structures A and D, which had already fallen out of use. Around 380 A.D. the site made a slight recovery from this decline. The pool was shored up by a series of conglomerate walls, built to hold up the earlier ones which were collapsing, so that the basin of the pool could be used as a drinking trough for animals. In this period a conglomerate basin was installed above the burnt remains of structure D, perhaps in an attempt to construct a simple bath structure using the spring present in the pool area. During the 5th century the site was partly abandoned and the drinking trough made out of the first pool was covered with clay. Occupation of the site continued and diverse finds of metal objects and late Roman coins suggest its occasional use, perhaps by shepherds.

Between the 9th and 14th centuries, in an attempt to improve access to the spring water, a well was dug. Moreover, at the south-eastern limit of Structure D a late building in re-used stone came to light; the quantity of bones found in the area suggests that it may have been a primitive form of animal stall. The latest evidence was provided by a 14th century Sienese coin. (MiBAC)