Aquae Calidae, Bulgaria well as from Kabyle, Mesambria (now Nessebar), Odessos, Histria, Tomis, Byzantium, Abdera, Maroneia and the islands of the Aegean, the oldest from Apollonia Pontica from the 5th century BC. The first baths at the Sanctuary of the Three Nymphs originated when the Roman Empire under Lucullus conquered the region, during the Third Mithridatic War in 72 BC. Under Trajan (98-117) nearby Anchialos became the administrative centre of the region and the baths were expanded and extended with two more swimming pools. During this time the Via Pontica was built connecting Constantinople via Deultum, Anchialos, Aquae Calidae with Dorostorum and Sexaginta
Christianity in Roman Britain introduced Roman counterparts were venerated in the region, sometimes syncretising together, as in cases like Apollo-Cunomaglus and Sulis-Minerva. Romano-British temples were sometimes erected at locations that had earlier been cultic sites in the pre-Roman Iron Age. A new style of "Romano-Celtic temple" developed which was influenced by both Iron Age and imperial Roman architectural styles but also unique from both; buildings in this style remained in use until the fourth century. The cults of various eastern deities had also been introduced to Roman Britain, among them those of the deities Isis, Mithras, and Cybele; Christianity was just one of these