
Rotunda of St George (Serdica Baths)
About
Constantine's building program raised this domed red-brick hall as part of a Roman bath complex in the early 4th century, making it the oldest standing building in Sofia today. The cylindrical drum measures 9.75 meters across at its base, its brick walls 1.4 meters thick, and the dome climbs nearly 13.7 meters overhead. It later hosted sessions of the Council of Serdica in 343 CE after conversion to a church. Nothing about it predates Hadrian's accession, let alone Trajan's death in 117 CE.
In ancient writing
- Bogdan Filov, Софийската църква „Св. Георги" (The Sofia Church of St. George) Bulgarian Archaeological Institute, 1933; further study 1939-1940
The excavation studies that first documented the hypocaust and brick construction identifying the Rotunda's original phase as a Roman bath building of the early 4th century, under Constantine, well after the 117 CE snapshot.
Sources
Nearby
Roman Maps shows the empire frozen at 11 August 117 CE, the day Trajan died — its moment of greatest territorial extent. Explore the full map →

