In line with the ancient Roman customs and traditions, in towns, besides the private baths, situated in luxurious private homes and villas, there were also several public thermae - baths. The best preserved Salonitan thermae are in the so-called Peter’s Street, to the east of the town basilicas, i.e. the Christian episcopal cemetery complex. This street was in the eastern, new part of the town, leading northward, to the town’s secondary gate. This area was excavated at the beginning of the twentieth century by F. Bulić and subsequently by W. Gerber.
These thermae are of somewhat smaller dimensions, yet they contain all the ambiance and rooms characteristic of Roman baths. These are an open peristyle, with a large pool, dressing rooms, cold- and hot-water swimming pools and other auxiliary rooms. Several indicators (sequence of constructing and inscriptions were taken from other places and built into the thermae structures) lead to the conclusion that the baths were built in the end of the second or the beginning of the third century, above remains of a private building rebuilt to serve the new purpose. Like other buildings in Salona, the thermae were rebuilt several times, but the initial layout is still quite evident.
In the late Roman époque, when Christian ideals got more established, public life and frequenting thermae was avoided and thermae lost their initial purpose: walls were partly painted white, and on the large columns there were cut crosses, symbols of the new ideology. Since water installations were required for both the thermae and the baptistery, some archaeologists (E. Dyggve, S. Piplović) deem that the thermae could have been turned into baptisteries at those early Christian times. Still, it appears impossible. Only fifty metres to the west there is an entire cathedral complex with baptistery, just about fifty metres away - unnecessary.