The 2014 excavations took place in insula IV, ix to investigate the block of buildings along the via della Marciana. A caupona of the mid 3rd century A.D. was identified in the courtyard of this block. A caupona was a public premises serving wine and other drinks, where one could gamble and enjoy the company of charming women. The coins recovered from the building, evidence of the intense use of the structure and of the lively commercial exchanges that took place there, date from the end of the Severan period to the first half of the 4th century A.D. The building was sumptuously decorated with wall paintings and mosaic floors. Outstanding for interest and quality was a mosaic showing the figure – preserved intact – of Pan fighting with Cupid. For this reason, the caupona has been named the “Caupona of the god Pan”.

The paucity of coins from the second half of the 4th century A.D. indicates and provides evidence for a change in the building’s use and ownership. A community of a Mithraic nature, perhaps in some ways syncretistic, occupied the structure for a short time having adapted it to its own needs.

The mithraeum, characterised by a very particular multi-colour floor, has been named the “Mithraeum of the coloured marbles”. The main room of the caupona probably became the initiation room, as suggested by the graffiti still preserved on the walls decorated by refined marmorisation. The mithraeum itself presents a number of peculiarities that clearly differentiate it from other mithraea excavated at Ostia. In fact, it was created for a small community affiliated to this religion, when it was by this time almost clandestine or even illegal. The structure was soon dismantled and blocked up, perhaps by the local authorities.