Predore: thermal baths of the Roman villa

In Predore, between the 1st century BC and the 4th century AD, there was a large villa, decorated with mosaics and frescoes and equipped with a thermal plant, situated in a scenic position on Lake Iseo, surrounded by fig and olive trees. The archaeological area allows a visit to the thermal plant.

In the underground of Predore are preserved the remains of a vast Roman villa that was inhabited between the 1st BC and the 4th century AD.

The existence of this building was already known thanks to a series of discoveries in the last century. In 2003, a large-scale construction project in the area occupied by the former Lanza Gomme factory brought to light a large portion of the important complex, which must have extended over an area of about 15,000 square metres, from the mountain slopes to the lake shore, which at the time was about 70 metres further back than it is today. To the east and west the limits were marked by the Rino and the Valle Muradella streams.

Inhabited since the first century BC, the villa underwent major building renovation between the second and third centuries AD, possibly due to the presence in the area of the family of senator Marcus Nonius Arrio Muciano, to whom the complex probably belonged. The same family owned a large villa on Lake Garda, partly enhanced in the archaeological area of Toscolano Maderno.

The building was provided with a thermal bath equipped with all the essential rooms for this type of structure. The caldarium consists of four rooms heated by a hypocausts: a series of pilae (small pillars) placed at regular intervals created a cavity under the floors through which hot air circulated. The air was heated thanks to a single praefurnium (oven) inside which a thick layer of ash was found, testifying to the prolonged use of the system. The tepidarium is represented by a circular room; the frigidarium, rectangular in shape, was covered with marble slabs and may have had a fountain. This was followed by a large pool (natatio) lined with slabs of local white stone.

The villa was also adorned with a rich decorative apparatus, as evidenced by the remains of mosaic pavements brought to light in several places and fragments of wall frescoes and stucco recovered during excavations.

In 2012 the archaeological area was opened and it is now possible to appreciate the thermal system of the villa; a series of panels guide the visit and support the understanding of the structures enhanced. The small antiquarium exhibits some of the artefacts found during the archaeological excavations. Among these, a brick stands out, reused as a slab to cover a gutter, one of whose faces is covered with graffiti of a different nature and not easy to understand. In one of the inscriptions, however, the words Neptunus, fluctibus and undas were recognised, a reference to Neptune and the world of water of great interest: it is suggestive to think that the geographical context may have inspired the author of the graffiti. It has been suggested that the object was originally used as a support for writing exercises, perhaps of a scholastic nature.

Graffito brick

One of the most interesting exhibits in the archaeological area of the Roman baths in Predore is certainly a graffito brick, originally used as a covering slab for a gutter of the villa’s baths, with one side covered in incisions, made before firing the artefact. The presence of inscriptions on Roman bricks is not uncommon, but these are generally signs referring to the activity of the figlina, the production plant where these materials were made. The peculiarity of the Predore piece lies in the fact that the graffiti is of a different nature: in addition to numerous signs that are difficult to interpret, one can distinguish the first four letters (A B C D) of an alphabetical sequence and some numbers, perhaps referring to writing and maths exercises. There are also two inscriptions in cursive capital: the first inscription consists of a single line, while the second consists of seven lines and has been crossed out by a series of vertical lines (erasures?).

Despite reading problems, the words Neptunus, fluctibus and und[a]s (or und[i]s) have been identified, thus a reference to Neptune and the world of water. The erasures seem to confirm the idea that this is a writing exercise.

Differences in graffiti orientation, strokes and graphic skills suggest that there is more than one doer, possibly engaged in a school exercise: in Roman society, lessons could take place in the open air, and it is therefore likely that a teacher would have taken his pupils to the brick-drying site, where they would have been provided with practical writing aids.

The engravings have been dated to a period between the end of the 2nd and the beginning of the 3rd century AD, a hypothesis that would be in agreement with the excavation data related to the installation of the channel.

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Thermal heating system

In the 2nd-3rd century AD, the Roman villa in Predore underwent a major building intervention, with the creation of the thermal baths, the remains of which are currently visible.

The baths appear to have the typical structure: a frigidarium (a room with a cold-water pool), a tepidarium (with warm water), and a caldarium (with hot water), adjacent to the frigidarium, but at a lower level, a part of a natatio (cold-water pool) was also excavated, which continues beyond the limits of the archaeological area. The caldarium, in particular, consisted of four rooms, located in the north-eastern part of the site, which were efficiently heated thanks to the presence of underground cavities, the hypocausts: from a hearth (praefurnium), located in a service room, the heat spread below the floors (suspensurae) of the surrounding rooms, which rested on a series of small pillars (pilae); this created empty spaces under the floor in which the hot air could circulate, before escaping to the outside through special vertical ducts in the walls (tubuli).

In the case of Predore, the suspensurae have not been preserved, but only fragments of stucco and painted plaster, presumably from the decoration of the walls of the caldarium; the pilae are mostly made of circular bricks and, especially in two rooms, their arrangement in regular rows is still appreciable.

All the hypocausts were served by a single praefurnium, in which a thick layer of ashes was found. Analysis of the wood charcoal also revealed the use of olive trees, which is important evidence of the cultivation of this plant on the lake in Roman times.