The excavation was led by Marija Jović and Gordan Janjić of Serbia's Institute of Archaeology and the Museum of Krajina. The team worked in the southwest tower of the palace at Vrelo-Šarkamen, north-west of Negotin. Beside the pools they found a sudatorium, the Roman sweating room, and a furnace room that still holds the base of a copper boiler. Under the floor, a hypocaust survives in good condition. Its round pillars held the floor up and let hot air from the furnace flow beneath it.
The other part of the tower belonged to the people who kept the bath running. Staff worked there to tend the fire and maintain the system. The emperor's rooms and his servants' workrooms shared the same stone walls.
The researchers know of no other Roman bath built inside a tower in this way, anywhere in the empire. They describe the arrangement as exceptionally rare.
The man who bathed here held power for only a short time. Maximinus Daza was named Caesar in 305 and claimed the title of Augustus around 310. This was the age of the Tetrarchy, when four emperors shared the Roman world. Researchers believe his mother was a sister of Galerius, whose own palace, Felix Romuliana, stands at Gamzigrad, not far away. Work at Šarkamen began around 309 or 310. By 313, Daza had lost to his rival Licinius at Tzirallum in Thrace, and he died at Tarsus later that year.
The site has kept its secrets for a long time. The traveller Felix Kanitz described the ruins as a fortification in 1889 and counted eight towers. The architect Đurđe Bošković counted ten when he surveyed them in 1947. Systematic excavations under Dragoslav Srejović began in 1994. Only then did the ruins give up their best-known find. In a mausoleum 250 metres west of the palace, probably built for Daza's mother, excavators found necklaces, earrings, rings and a gold diadem. Its leaves carry stamped portraits of the tetrarchs.
Three decades later, the palace has revealed its bath. The emperor's family built a tomb for the dead and warm water for the living, and both have now been found.