Ostia - Architecture and technology
The largest baths in Ostia were called thermae, not balnea, as we might expect in view of their size and rich decoration. Two full names have been preserved in inscriptions. The Baths of the Forum were called Thermae Gavi Maximi, after the Praetorian Prefect Marcus Gavius Maximus, who had financed them. They were restored during the reign of Theodosius (379-395 AD), probably financed by Ragonius Vincentius Celsus, Prefect of the Food Supply in the years 385-389 AD. A statue found in the palaestra may represent him (inv. nr. 55). The Baths of the Marine Gate were called Thermae Maritimae, and in a very late inscription Thermae Marinae (the early excavators applied the name erroneously to baths further to the west, still known today as the Maritime Baths). The name was derived from the seashore, at which these baths were situated. They were financed by Hadrian and Antoninus Pius. The late Historia Augusta mentions a lavacrum Ostiense built by Antoninus Pius, perhaps to be identified with the Thermae Maritimae.
The three largest baths (the third one being the Baths of Neptune) had a fairly regular lay-out, with rooms next to a spacious palaestra. Particularly noteworthy is the orientation of the bathing rooms of the Baths of the Forum. In Ostia the sunlight moves from the south-east to the south-west, and the rooms face the south-west, so that they would catch the maximum of sunlight during the preferred bathing hours, in the afternoon. The windows in this facade are very large, and most contained glass panes in wooden frames. Vertical bands of mortar have been preserved that were used for fastening the frames.
Reconstruction drawing of a heated room, by Aldo Pascolini.The numerous smaller baths, the balnea, tend to have a rather irregular lay-out, which may have been caused by the available space or technical considerations (heating and water supply). Sometimes later modifications led to some irregularity. For physical exercise small courtyards may have been used, for example in the Baths of the Philosopher and the Baths of the Jealous One. In the latter baths a dressing room could be identified because of the presence of niches for clothes (for some reason these were later filled in).
Little is known about the owners of these smaller baths. In the Baths of Mithras two "shields" were found with portraits of, presumably, financiers (inv. nrs. 56 and 57). Another "shield", for a lost portrait, was found in the Baths of the Forum (inv. nr. 1222). On the basis of stamps on lead waterpipes it has been argued that the Baths of the Lighthouse were owned by Roman senators and for some time by Cornificia, either the sister or the daughter of Marcus Aurelius. In two baths, the Baths of the bathing attendant Epictetus Buticosus and the Baths of the Seven Sages, a caretaker was depicted in a mosaic floor. Next to a naked man is a text: EPICTETVS BVTICOSVS and IVLI CARDI H(ic) C(onspicitur) E(ffigies) ("Here one sees a likeness of Iulius Cardius"). Buticosus is a nickname of Epictetus, perhaps meaning that he talked a lot about his native city Butos in the Nile delta. There are no parallels for the suggested explanation of the abbreviation HCE, which normally means hic conditus est ("is buried here"). The text might be ambiguous and the image may have been intended to show and remember a popular caretaker after his demise. Through the mosaic he would then have been laid to rest forever in his beloved baths and in the minds of his clients.
Quite remarkable are two tiny baths: the Small Baths to the west of the Baths of Mithras, from the period 450-550 AD, and the Baths in Warehouse III,XVII,1, from the fourth century AD. They do not have an obvious relation with a nearby building. Surely their late date is, somehow, significant. The only set of bathing rooms that is clearly private has been found in the House of the Dioscures.
Lead pipes below the floors of the baths show that water was adduced by the aqueduct. This reached the city a bit to the south of the Roman Gate. Below the Decumanus is a main conduit (a short stretch can today be seen through a metal grate). The water was also transported on top of the old city wall, to the south of the city. To the east of the Baths of the Forum are two huge arches with two storeys, looking at first sight like part of an aqueduct. That makes no sense at all however on this spot. Also, the arches reach a height of 13.9 metres above sea-level, whereas the Ostian aqueduct arrived at the city at a height of 8 metres, which gives us the maximum level of water pressure. Apparently these were symbolic arches.
It is quite possible that rain water was collected in basins on upper floors. For several baths ground water was lifted with the help of huge waterwheels. The wheels were put in motion by people walking inside the wheel. In the Baths of the Coachmen a substantial part of the actual wooden wheel was excavated not long ago. In the Baths of the Forum a wheel was used inside the building, but a system of cisterns and waterwheels in the neighbouring House of the Cistern (I,XII,4) may have served the baths as well. In the Baths of Mithras the water was lifted in stages, by several wheels. Wheels are also documented in the Baths of the bathing attendant Epictetus Buticosus, the Baths of the Trinacria, the Baths of the Six Columns, the Baths of the Jealous One, and - on the Isola Sacra - the Baths of Matidia. The water was also used to flush communal latrines.
The service areas consist of narrow corridors and rooms with ovens. Here slaves controlled the flow of the water and the heating system. The area has been preserved particularly well below the Baths of Mithras. It is closed to the public however, because walking in the dark and slippery corridors is tricky. The mithraeum that gave the building its name was installed here, and also a tiny fullery. The service area of the Baths of the Jealous One is also in good condition. It can be entered from the road to the south of the baths.
A small part of the underground service area in the Baths of Mithras. Photo: Wikimedia, Lalupa.
