The Baths of the Porta Marina are located at a considerable distance from the Sea Gate, towards the south-east. The building was searched by the Scottish painter Gavin Hamilton, who mentions it in a letter from 1775 (see below). It was partly excavated by Pietro Campana in the years 1831-35. Further excavations took place in the years 1922-1928, 1938-1942, and 1971-1973, followed by restoration. An inscription from the late fourth century AD mentions the ancient name: Thermae Maritimae, i.e. Sea Baths (thermas maritimas intresecus refectione cellarum, foris soli adiectione; CIL XIV, 137). The building was erected during the reign of Trajan (opus mixtum), probably by the Imperial family. Portraits of Plotina and Marciana, wife and sister of Trajan, were found in the building (sometimes the baths are referred to as Terme della Marciana). The building activities continued until the end of the reign of Hadrian. Alterations took place in the first half of the third century, in 375-378 AD, and in the period 493-526 AD (an exceptionally late date in Ostia).
At the north end of the building is a palaestra with a porticus on three sides (1). To the south-west is an apodyterium (2). In room 3 is a geometric black-and-white floor mosaic. Room 4 is a large frigidarium. Bases for statues were found here. On the floor is a polychrome geometric mosaic, made with large tesserae in the fourth or fifth century. In the north-west part is a black-and-white mosaic with athletes in a palaestra, made in the third century (see below). At the south end are two large basins. At the north end is an apse with a basin, the apse being an addition from the third century. The brick piers of the apse have always been visible. The frigidarium could also be entered from the east. In vestibule 7 is a black-and-white mosaic with Nereids. In transitional room 6 is a black-and-white mosaic with fishes. Both mosaics belong to the third century. The heated rooms, including two apsidal tepidaria, are to the south of the frigidarium.
The south part of the block (IV,X,2) was originally a service area of the baths. Later, perhaps in the fourth century (opus vittatum), it became a separate small bathing complex. It is arranged around a central courtyard (8). It could be entered from the Via Severiana, that is to the south of the baths: in the south-east corner of the building a porch leads to room 9. An embankment was found nearby, that may well be mentioned by Minucius Felix in his work Octavius: "Let us be seated on those rocky barriers that are cast there for the protection of the baths, and that run far out into the deep ...". Do not think that you can relive this moment, in a romantic mood. A busy highway is at the spot of the ancient beach.
Gavin Hamilton's letter to Lord Townsend, written in 1775
"Being desirous of trying my fortune somewhere near the sea, I agreed with Cardinal Serbelloni, then Bishop of that place, who granted me liberty to make some trials in that immense field of antiquity. I got as near the Sea as possible, judging it the most probable place to find objects of taste. We opened ground on a spot now called Porta Marina [this is a reference to the brick piers of the apse to the north of the frigidarium - jthb]. From the figure of the ruins they proved to be the remains of publick Thermae Maritimae, and from the inscriptions which were found of an unusual size, it seems those Baths had been restored by different Emperors down to Constantin. I gave a very elegant one of the time of Trajan to Carlo Albagine [disappeared - jthb], but what gave me greatest hopes was to find some marks of my friend Hadrian, the great protectour of fine arts and in particular that of Sculptour. I did not remain long in suspense, for the first Statue that was brought to light was the fine Antinous in the character of Abundance, perhaps the finest of that subject in the world. Mr. Bary tells me it is arrived safe at his house in England, and where I hope by this time you have had the pleasure to consider it. Near this Statue was found a very indifferent one of an Esculapius, and a large statue of his daughter Hygea, very entire, and of a great deal of merit; this Statue was sold with some other pieces of good sculptour to the Langrave of Hesse Cassel. We found next a most excellent Torso under the knees, of which there is a duplicate at the Capitol. ...Little more of consequence was found at Porta Marina, as I found that others had been there before me, so we proceeded to another Ruin on the sea shore, which from some fragments found above ground gave great hopes. A Bath [the same building or perhaps the Terme Marittime (III,VIII,2) - jthb] was first discovered with the pavement of Verd antique and a fine Torso of a young man of which most of the other parts were found much broke, excepting the Head. ...Your small Venus holding a mirror is another of the precious ornaments of this Bath; four of the Labours of Hercules were found at some little distance from this place, which being very entire, and with their proper emblems, now add to the lustre of the Pope's Museum, to which I may add that tasty Tripod of Apollo, found near where we discovered your Mother of Venus and Muse, which, as they are in every respect two of my happiest discoveries, I am very happy that they should fall into so good hands as your own, especially as they make part of those select pieces of art which I hope will in time establish a good taste in England." (Meiggs 1973, 103-104)
The four Labours of Hercules were actually found in a lime-kiln. They are now in the Sala degli Animali of the Vatican Museums (Palma 1978-1980).
The mosaic with athletes
This mosaic was discovered in the early 1970's, in what may have been an apodyterium. In the centre is a table with prizes. On the right half is a large, decorated crown with three rays. The size is disproportionate, so that many details could be shown. Perhaps it was made of metal. Some of the "incisions" may represent gems. To the left is a palm branch. To the right of the table is a herm with another palm branch. A hoop is leaning against the herm. Next to the hoop is a short stick with a curved end, used to steer the hoop. In front of the table, from left to right, are a metal bowl on a high foot, a leather ball, a vessel with a handle (probably for oil), and a ring with three strigiles.
The way in which the ball (pila lusoria) is depicted is rather surprising, because it is a "bucky ball" or "fullerene like ball", i.e. with pentagonal and hexagonal faces. A bucky ball is a geometric figure consisting of 12 pentagons and (what makes it special) a number of hexagons. The ordinary soccer ball is a bucky ball. Chemists have discovered that there is a special form of carbon, C60, shaped like a soccer ball. The people who discovered C60 received the Nobel prize for chemistry in 1996. The names bucky-ball and fullerene refer to the American architect Buckminster Fuller, who - especially in the nineteen-sixties - built large domes of aluminum five- and six-rings. According to Rassat and Thuillier the Ostian ball could be a representation of a hexadecahedral ball (12 pentagonal and 4 hexagonal faces), but is probably an erroneous representation of a regular dodecahedral ball (12 pentagonal faces): two pentagonal faces were wrongly drawn as hexagons.
Below the table two boxers are depicted. The one to the left, raising both arms, has won. The one to the right is protesting to a bearded referee to the right. To the right of the referee is a herm. To the right of the table is an athlete holding weights (halteres) used in the long jump (or perhaps he is training with weights). Above the table four athletes can be seen. The first one is carrying a ring to which two strigiles and a vessel with oil are attached. In his other hand may have been a palm branch (the mosaic is damaged here). The second one is carrying a strigilis. To the right are two wrestlers. Finally, to the left of the table, we see a discus-thrower. The discus is in his right hand, his left arm is raised, perhaps indicating victory. To his right is a trumpeter. He is not announcing the start of the competition, but has won a prize in a musical competition. His left arm is raised and with his left hand he is holding a crown on his head. The crown is very similar to the one on the table. It has four rays instead of three.
Plan of the baths. From Pavolini 1983.
The portrait of Marciana.
Valeri 2001, fig. 7.