underneath that supply water to the bathhouse. Regio IV (Outside the City Walls) Baths of Musiciolus The baths of Musiciolus (IV,XV,2) are in the mostly unexcavated area between the Porta Marina Baths and the Synagogue. The original building was constructed during the reign of Antonius Pius, but the baths were not installed until the reign of Septimius Severus and a restructuring of the complex under Constantius II in 347-348 C.E. The structure has an entrance hall, frigidarium and four small heated rooms, in which black-and-white and polychrome geometric mosaics were discovered. The central room had a mosaic with the heads of four athletes and a referee, but that was stolen shortly after its discovery. The heads were all named, the referee was called Musiciolus ("Harmonious" and the namesake of the bathhouse), and the four athletes were called Faustus (lucky), Ursus (bear), Luxsurius (Voluptuous), and Pascentius. Faustus is shown with a victory palm, and in the small apse are a set of long jump weights and strigils and a metal oil vessel. This mosaic most likely was installed during 4th century C.E. renovations. Baths of the Skeleton This small bathhouse (IV, IX, 6) was a balneum built into the fabric of the house, but have only been partially excavated. The bathhouse was added during the 4th century C.E. It was named after the discovery of a human skeleton in room 15, in 2014. The only rooms that were exposed were those related to the heated rooms. A nummus of Theodosius was recovered from a secure context indicating that the bath remained in use during the first half of the 5th century C.E. until the earthquake of 442 C.E., when the structure most likely was abandoned. Baths of Silenus The Baths of Silenus (IV, IX, 7) were discovered in 2011 as a part of the work of the Ostia Marina Project at the University of Bologna. The 400-square meter structure was built along the ancient coastline in the extra-urban neighborhood beyond the Porta Marina Gates. Brick stamps recovered suggest an initial construction of 123-126 C.E. with later reuse during the Late Antique period of Ostia The name comes from the marble revetment depicting Silenus. The baths appear to be a part of suburban revival initiated by Hadrian in the Porta Marina area in conjunction with the Porta Marina Baths. Porta Marina Baths These baths have also been called by modern archaeologists both