The originally Ancient Thracian city of Aquae Calidae (meaning “hot waters" in Latin) is an archaeological site located on the territory of Bulgaria’s Black Sea port city of Burgas, on the site of today’s Burgas quarters of Vetren and Banevo. It is proven that Aquae Calidae – known in the Middle Ages as Thermopolis or Therma – was visited by important ancient and medieval rulers such as Philip II of Macedon (r. 359-336 BC), Byzantine Emperors Justinian I (r. 527-565 AD) the Great and Constantine IV the Bearded (668-685 AD), Bulgarian Khan (or Kanas) Tervel (r. 700-718/721), and Ottoman Turkish Sultan Suleiman the Magnificent (r. 1520-1566 AD). Archaeological excavations have found that the Aquae Calidae mineral baths were used as early as the Neolithic Age, with three prehistoric settlements being located there in the 6th-5th millennium BC.
The Ancient Thracians settled near the mineral waters in the middle of the 1st millennium BC, turning the major spring into the revered ancient “Sanctuary of the Three Nymphs" by the middle of the 1st century AD when the Roman Empire was wrapping up the conquest of Ancient Thrace. The earliest written testimony about the ancient spa resort Aquae Calidae dates back to the 4th century BC when Philip II of Macedon went there. The name b comes from the name of a Roman road station near the mineral springs which was erected along the major Roman road Via Pontica running along the Western coast of the Black Sea. The Sanctuary of the Three Nymphs was revered in Roman times. The Roman baths at Aquae Calidae were rebuilt and expanded in the early years of the Byzantine Empire – the 4th-5th century, with fortress walls constructed during the reign of Emperor Justinian I the Great.
In the Middle Ages, Aquae Calidae became known as Therma or Thermopolis (“warm city" in Greek). In 708 AD, Khan (or Kanas) Tervel, ruler of the First Bulgarian Empire, defeated the army of Byzantine Emperor Justianian II (r. 685-695 and 705-711 AD) in the first Battle of Anchialos close to Thermopolis, conquering the ancient and medieval “spa resort" for Bulgaria. Another interesting episode from the history of Thermopolis has to do with the so called Latin Empire established when the knights from the Fourth Crusade conquered Constantinople.
After Tsar Kaloyan (r. 1197-1207 AD) of the Second Bulgarian Empire defeated the crusaders in the Battle of Adrianople in 1205 and captured Latin Emperor Baldwin of Flanders (also Baldwin I of Constantinople), the next year the Latin Emperor’s brother, Henry of Flanders, marched against Bulgaria conquering Thermopolis, looting the city and burning it to the ground. The city of Thermopolis never recovered even though the mineral baths themselves were rebuilt later and used by Ottoman Turkish Sultan Suleiman I the Magnificent in 1562. In modern-day Bulgaria, in the 20th century the town near the mineral baths was known as Banevo until the 1980s when it was renamed to Burgas Mineral Baths; it became part of the city of Burgas in 2009.
Aquae Calidea – Thermopolis was first excavated in 1910 by renowned but controversial Bulgarian archaeologist Bogdan FIlov (known as Bulgaria’s pro-German Prime Minister during World War II). The contemporary excavations were started in 2008 by Senior Fellow Tsonya Drazheva and Ass. Prof. Dimcho Momchilov. In 2011, the ancient and medieval city was formally declared “The Aquae Calidae – Thermopolis Archaeological Preserve".