Cardia was founded as a joint colony of Miletus and Clazomenae, two Ionian Greek cities on the western coast of Anatolia. The Gulf of Melas — today's Gulf of Saros — opened to its south, giving the city a sheltered anchorage and command of the water route through the Dardanelles. Miltiades the Younger, the Athenian general who would later win at Marathon, served as tyrant of the Chersonese between roughly 515 and 493 BC. During his tenure the city received Athenian colonists, which might have been expected to anchor it in the Athenian orbit. It did not. Geography and trade pulled Cardia in different directions than Athenian ideology preferred, and the city developed a habit of independent judgment that its powerful neighbors found inconvenient.

When Athens reasserted control over the Chersonese in 357 BC, Cardia was the only city on the peninsula to remain neutral — operating, apparently, under the authority of a Thracian prince rather than submitting to Athenian governance. The decisive moment came in 352 BC, when Cardia concluded a formal treaty with Philip II of Macedon. This made the city a Macedonian ally in the heart of a region Athens considered its own. The crisis sharpened in 343 BC when an Athenian mercenary commander named Diopeithes arrived with Attic settlers and attempted to install them in Cardia. The city refused to accept them. Philip sent help immediately. Athens faced a choice between accepting Macedonian influence on the Chersonese or escalating toward a confrontation it was not prepared to win. Demosthenes pushed for confrontation; the assembly hesitated. Within a generation, Philip's son Alexander had resolved the question by making every Greek city's sovereignty largely theoretical.

Two of the most significant figures of the age of Alexander came from Cardia. Eumenes served as Alexander's chief secretary and, after the king's death in 323 BC, became one of the most capable commanders in the wars among Alexander's successors. He was not Macedonian by birth — the Macedonian generals who fought alongside him never fully trusted him for that reason — but his administrative skill and military competence kept him in the field for years against opponents who considered him an outsider. Hieronymus of Cardia was a historian and, like Eumenes, a survivor of the post-Alexander decades; he lived to old age watching and recording the world created by the Diadochi. Plutarch later noted that the young men and boys of Cardia trained in the pankration and wrestling — the hard, grappling athleticism that the Hellenistic world valued alongside its military arts.

Around 309 BC, Lysimachus — one of Alexander's generals who had carved out control of Thrace — destroyed Cardia. The inhabitants were not killed but displaced: Lysimachus forcibly relocated them to populate his new capital, Lysimachia, built on the isthmus a few kilometers away. The transfer was total enough that Cardia never recovered. It was eventually rebuilt, but the ancient sources agree it never regained any real prosperity. Its strategic position at the head of the gulf, which had made it valuable for centuries, now made it a liability — too close to Lysimachia to be allowed an independent identity. The city that had negotiated with Miltiades, defied Athens, allied with Philip, and produced Eumenes and Hieronymus faded into the agricultural margins of the Thracian Chersonese. Today its site lies beneath the soil near the village of Bolayır, without a monument.