Ancient Greek colony and Roman centre
Possibly founded in the 5th or 4th century BC as a colony of Apollonia (today Sozopol), Anchialos was mentioned inStrabo's Geographica as a small town. It was briefly captured by Messembria (Nesebar) in the 2nd century BC, but reconquered by Apollonia and its fortified walls destroyed.
The western Black Sea coast was ultimately conquered by the Romans under Marcus Licinius Crassus in 29-28 BC after continuous campaigns in the area since 72-71. The fortified wall was meanwhile rebuilt, as evidenced by Ovid in 9 AD en route to Tomis. In the early 1st century AD Anchialos was the centre of a strategia of the vassal Odrysian kingdom, and the town had a Thracian population in the 6th century AD according to the early Byzantine historian Procopius. As the Odrysian kingdom's self-independence was abolished in 45 AD, Anchialos became part of the Roman province of Thraceand was formally proclaimed a city under Emperor Trajan. At the time the city controlled a vast territory bordering that of Augusta Trajana (Stara Zagora) and reaching the Tundzha to the west, bordering that of Messembria to the north and the southern shore of Lake Burgas to the south. Anchialos acquired the appearance of a Roman city and throve in the 2nd and 3rd century under the Severan Dynasty, serving as the most important import and export station of Thrace.
Early Byzantine rule
However, the invasion of barbarian tribes from the north meant an end to this prosperity in the middle of the 3rd century, with the Goths briefly capturing Anchialos around 270.Diocletian stayed in the city between 28 and 30 October 294. His and Constantine the Great's reforms restored the city's prosperity for a while, as the proximity to the new capital ofConstantinople made Anchialos a key food supply centre.
Theodoric the Great passed through the city in 476 on the way to Adrianople. A high-ranking Byzantine general named Vitalian in 513
