The Baths of the Silenus were discovered in 2011 by the Ostia Marina Project (University of Bologna, under the direction of Massimiliano David). It has received this name after the discovery of a fragment of a Dionysiac frieze with masks of Silenus and a Faun.
The baths are a big complex, dated to the late Hadrianic period on the basis of several brick-stamps found in place. The building has a series of rooms on two main axes. In the east-west axe the frigidarium (room 6) has been identified. Room 7 is a large pool (natatio) with niches for statues and a monumental entrance. Two marble columns with Corinthian capitals (found still in place, incorporated in later walls) adorned the south entrance. In room 8 a wonderful geometric black-and-white mosaic was found. The heated area and the palaestra have not been excavated yet.
The lifespan of the building lasted until at least the second half of the fourth century AD, when conspicuous alterations are seen. The natatio in room 7 was filled and a new marble floor was made on top of the fill. The entrance was reduced, incorporating the columns in the new walls.
Plan of the baths with the major building phases.
Green: Hadrianic phase. Blue: second phase.
Yellow: second half of the fourth century.
David et al. 2015, fig. 1.