XVII, 1 This warehouse was built during the Hadrianic Period and most likely was privately owned. During the fourth century C.E. a set of rooms in the south end of the building was converted into a bath suite with mosaics. This balnea, along with several other refurbished bathhouses, served the Late Antique population of Osita. Regio IV (Inside the City Walls) Baths of the Lighthouse The Baths of the Lighthouse (IV, II, 1) have a long history of use, originally started during the late Trajanic/Early Hadrianic Period with renovations during the late Antonine/early Marcus Aurelian period, again during the reign of Caracalla, during the last quarter of the 3rd century C.E., and during the 5th century C.E. Flanking the entrance are shops and a thermopolium. The frigidarium contains 3rd-century frescoes of Europa and the Bull and Venus carried by Tritons and a Nereid. The namesake mosaic can be found in the floor of the frigidarium where fish and sea monsters surround a lighthouse (pharos). The lighthouse and a marine goat are the main compositional figures and the are surrounded by smaller marine creatures and black lines that represent water. Stamps on the fistulae is used as evidence that the ownership of the baths changed three times, between some Roman Senators and either Cornificia or Cornificia Minor. Baths IV, V, 6 These small baths were built behind a commercial building during the Antonine period. It is poorly preserved and on the edge of the excavated area. Byztantine Baths It is unclear why these baths (IV, IV, 8) were give this name. They are evidence of the Late Antique inhabitation of Ostia being built between 390 and 425 C.E. They were constructed in a perisytlium of the House of Jupiter the Thunderer. There are many geometric mosaics found throughout the rooms here, additional the bathhouse has 10 apses, which could be the inspiration for its modern name. Baths of the Six-Columns This bathhouse (IV, V, 10-11), named for the six columns found in its courtyard, was along the western half of the Decumanus. It has several phases of construction, from the first half of the 2nd century C.E. through the Severan period. A cache of republican period coins in a bronze vessel was in its foundation. Like many of the smaller bathhouses, this one was set into the existing urban fabric with bars, shops, and apartments surrounding it. There are several reservoirs