On the glass flasks we read STADIVM and see depictions of a stadium, a building for athletic contests. Remains that could have been the stadium have been known for a long time. A partial plan by Tommaso Rajola was published in 1768, and a plan with cross-section by Auguste Caristie in the 1820's. For a long time there was confusion about the function of this building. The plan showed two curved sides instead of the usual one, but one of these was only hypothetical. The building seemed to be too large for a stadium, but too small for a circus.

Plan and cross-section of the stadium from the 1820's by the French architect Auguste Caristie.
Image: Camodeca 2001, fig. 2.

Further research in 1986-1988 and 2005-2008 showed that we are indeed dealing with the stadium, with the usual measurements: about 265 meters long and 70 metres wide, with an arena that was about 40 meters wide. The masonry is opus mixtum and opus latericium.

Plan of the stadium after the 1986-1988 investigations by Camodeca.
Image: Camodeca 2001, fig. 4.

The remains of the stadium.
Photos: Camodeca 2018, pp. 259-260.

The stadium is today crossed by a modern road.

More than fifty Greco-Roman stadiums are known, but most of these are in Greece and Asia Minor. In the Latin-speaking west they are documented only in Rome (the Stadium of Domitianus, now Piazza Navona), Marseille, Naples, Cumae and Puteoli, apart from Rome all cities with a Greek cultural background and character. Giuseppe Camodeca has argued convincingly that the stadium was erected by Antoninus Pius in memory of Hadrian. Hadrian had died in Puteoli and had been buried temporarily in a tomb on the terrain of a villa that had once been owned by Cicero. Antoninus Pius built the stadium on the spot of the temporary tomb, choosing a "Greek" building because of Hadrian's philhellenism.

Camodeca's argument rests on the institution by Antoninus Pius of athletic games in memory of Hadrian, taking place in Puteoli every five years. These games are mentioned in the Historia Augusta, in the account of Hadrian's death. In Greek they were called Eusebeia ("reverence towards the gods"):

I know of a stadium-runner who was about to compete in the Eusebian games in Italy which were first instituted by the emperor Antoninus in honor of his father Hadrian. He won after he dreamt that he had gone blind. For like a blind man, the man who takes the lead in a race does not see his fellow-competitors.

Artemidoros, Oneirocritica (Interpretation of Dreams) I,26. Translation R.J. White.

The "first Eusebeia" are mentioned in an inscription set up by the city of Naples for the flute player P. Aelius Antigenidas, who won the musical contest (IG XIV, 737; in Puteoli's odeum?). This edition must have taken place in 142 AD, together with the inauguration of the stadium. The Puteolan games are then mentioned in a whole series of Greek inscriptions in honour of winners (boxers, wrestlers, runners, flute players), found in Italy, Greece and Asia Minor (Moretti 1953, nrs. 73, 76-79, 81, 84, 87-88, 90).

A reference to the Eusebeia is found on a black-and-white mosaic that was discovered in Pozzuoli in 1998. It belongs to the first half of the 3rd century. Two pairs of boxers are depicted, and the names of three of these have been preserved above them: Helix, Magira and Alexander (two of them can also be seen on a mosaic in Ostia, in the Caupona of Alexander and Helix (IV,VII,4)). In a tabula ansata in the centre are the words ISEO EVSEBIA. For ISEO no satisfactory explanation has been found; "in the Iseum" perhaps?

The mosaic of the boxers.
Photo: Caldelli 2008, fig. 1.

The Historia Augusta also says that Antoninus Pius built a temple for Hadrian "to take the place of the tomb" (pro sepulchro). It must have been near the stadium, but no remains have been identified.