Paleohydrographic studies show that approximately 2,500 years ago, the Black Sea coastline lay several leagues east of present-day Chilia Veche, as the Chilia arm and its secondary deltas had not yet formed. Greek merchants maintained a community here called Achillea (or Licostomo, depending on the period), an active port on the Black Sea (Pontic Euxine) route.
Archaeological research has revealed two burial mounds at a site called "Ciorticut", south-east of Chilia Veche. At "Selesce", excavations uncovered clay pipes, ceramics, coins and grain storage pits — evidence that the original settlement lay not where the village stands today, but further south, on the banks of the Chilia-Batag channel.
The Chilia arm appears in Byzantine and Genoese chronicles under the name Lykostoma (Greek: "wolf's mouth") or Licostomo, which also designated the fortress-port near present-day Periprava. It was the Delta's main navigation route, contested over millennia by Byzantines, Bulgarians, Russians, Tatars, Genoese, Dobrogeans, Wallachians, Moldavians and Ottomans.