The Propontis forms the geographical and historical entry to the Black Sea . From the seventh century BC to the fourth century AD the key-city which kept the roads of communication open was called Byzantion.
In 330 AD the emperor Constantine the Great brought the capital of the Roman Empire to ancient Byzantion , which was renamed Constantinople, after the emperor’s name. Byzantion-Constantinople, located on the northest tip of the Propontis, kept the passage of the Symblegades (jostling rocks) continuously open for twenty six centuries.
The Istros-Danube and Metropolitan Istria
The river Danube has its sources in the Black Forest and flows into the northwest of the Black Sea, forming a broad, extensive delta. Istria, the most important metropolitan colony on the west coast of the Black Sea was built on a peninsula. When, in 330 AD, the emperor Constantine transferred the capital of the Roman Empire from the West to the East, the Danube border became the spine of Byzantine defences. Most commercial activity was transferred to Tomis (the present-day Constantza).
From the Danube Delta to the Bosphoros
Southwards from the riverine and maritime Istria a series of large and small coastal colonies and anchorages was created The earliest of these colonies was ApolIonia, the Byzantine Sozopolis, the present Sozopol.
Penetration to the Hinterland of Thrace and the Early Hellenization of the Ancient Thracians
In the middle of the fourth century BC, when Philip II, the king of Macedonia, had conquered the Thracian coast from Aegean to the Propontis ,right in the middle of present day Bulgaria Philip founded Philippoupolis. The city is located on the principal road-artery connecting the Aegean with the Danube. Alexander, Philip ‘s son, was the first to cross this axis and reached the great river with his army, in May 335 BC.
The ancient Greek Chersonisos -Byzantine Cherson – Modern Sebastopol
At the southwestern end of the Crimea, where the Tauroi head-hunters lived, the Dorians from Herakleia of Pontos founded the city of Chersonesos in 422 BC. Its exceptional harbour is the present naval base of the Soviet Black Sea fleet.
The Kingdom of Pontos or the Kingdom of the Mithridatians 302 (?)-64 BC
The cradle of this peculiar “Hellenistic” kingdom was Amaseia, a well-fortified city in the hinterland of Pontos, built on the top of a ravine of the river Iris. The account of its foundation is directly associated with the campaign of Alexander the Great in western Asia.