Odessa, Thrace is Varna, Bulgaria today. Miletian Greeks founded an apoikia (trading post) at the Thracian settlement around 600 B.C., creating a mixed Greek and Thracian community. Philip II besieged the city in 339. Getae priests persuaded him to make a treaty but the city surrendered to Alexander the Great in 335 B.C.

Odessus, along with other Pontic cities and the Gatae, rebelled against Lysimachus in 313 B.C. After Lysimachus' death in 281, the city reverted to striking in the types and names of Alexander the Great and continued to strike Alexandrine tetradrachms until at least 70 B.C. After the Battle of Pydna in 168 B.C., Thrace passed to Rome. The Thracians, however, did not all readily accept Roman dominion. Several revolts occurred. The next century and a half saw the slow development of Thracia into a permanent Roman client state. According to the Bulgarian Orthodox Church, Ampliatus, a follower of Saint Andrew preached in the city in 56 A.D. Public baths erected in the late 2nd century A.D. are the largest Roman remains in Bulgaria and the fourth-largest known Roman baths in Europe.

Source: http://www.forumancientcoins.com/catalog/roman-and-greek-coins.asp?vpar=1557