To found Lysimachia, Lysimachus did not simply choose an empty site. The isthmus already held Cardia, an ancient Greek city with centuries of history and notable citizens, and other Chersonesean settlements. Lysimachus destroyed Cardia around 309 BC and forced its population to relocate to his new city. The inhabitants of the surrounding towns followed. This was the founding act: a Hellenistic capital built not organically but by decree, populated not by voluntary migration but by compulsion. The Roman historian Justin records the scale of the dislocation. Ancient sources agree that Lysimachia rose rapidly to great splendor and prosperity under its founder — the strategic position alone ensured that; whoever held the isthmus commanded the traffic between Sestos on the Dardanelles and the Thracian mainland to the north. Lysimachus made it his capital and its growth reflected the resources of a kingdom that stretched from Thrace across to western Anatolia.

In 287 BC the city was severely damaged by an earthquake, as the Roman historian Justin recorded. It recovered. Then Lysimachus died at the Battle of Corupedium in 281 BC, and Lysimachia passed to the Seleucid Empire. In the shifting wars between the Seleucids and the Ptolemies over the following decades, the city changed hands, eventually entering into a formal alliance with the Aetolian League. In 197 BC, during the Roman war against Philip V of Macedon, Thracian forces sacked Lysimachia — destroying it again and, by Roman accounts, killing or enslaving much of the population. The Seleucid king Antiochus the Great stepped in to restore it: he gathered the scattered survivors, freed those who had been enslaved, and attracted new settlers with generous offers. This restoration proved short-lived. As Rome consolidated its dominance over the eastern Mediterranean, Lysimachia declined more and more. The city had been rebuilt twice; its momentum was gone.

In 277 BC, a significant battle was fought near Lysimachia that had nothing directly to do with the city itself but underlines how strategically active this stretch of Thrace was. The Macedonian king Antigonus II Gonatas defeated a Gaulish force near Lysimachia — an engagement known as the Battle of Lysimachia. The Gauls had been moving through Thrace and the Balkans since around 279 BC, a migration that had brought them as far as Delphi before pressure from Greek and Macedonian forces pushed them back. The battle near Lysimachia helped confirm Macedonian authority in the north and gave Antigonus the prestige he needed to consolidate his rule. For the city itself, being the setting of a major Macedonian military victory may have provided some protection; the city was already allied with the Aetolians and navigating a period of complex political geography.

The last ancient reference to the city under its original name appears in the fourth-century historian Ammianus Marcellinus. After that, silence — until the emperor Justinian (527–565 AD) restored it and surrounded it with strong fortifications. By then the city was known only as Hexamilion, a name derived from the Greek word for six miles, describing the length of fortifications across the isthmus. The modern village of Eksemil, which sits near the ancient site, preserves that Byzantine name in its own. The ruins of the Hellenistic and later city are most visible not at Eksemil but in the neighboring village of Ortaköy, where excavations and surface surveys have found material from multiple periods. What was once a Hellenistic capital, then a Byzantine fortress, is now a scatter of stones in farmland near the shore of the Gulf of Saros — the isthmus it was built to command still perfectly legible in the landscape, still narrow, still the hinge between two worlds.