Rome defends Olbia against the Tauro-Scythians

Olbia, the old Milesian colony on the estuary of the Southern Bug, never regained its former size after the Getae of Burebista sacked it in the mid-1st century BC. Dio of Prusa, who visited it, probably during his exile under Domitian, found a shrunken town that had shut its gates and raised the war standard after a Scythian raid. According to V. F. Gaidukevich, in the mid-1st century AD Olbia even had to accept the overlordship of the Crimean Scythian kings and strike coins in the names of Pharzoios and Inismeus (today they are more often regarded as Sarmatian kings). In the 2nd century the threat came from the Tauro-Scythians — the Scythians of Crimea, mixed with the Tauri of the mountains.

The episode is known from a single sentence in the Life of Antoninus Pius in the Historia Augusta: the emperor sent auxiliaries to the Pontus to help the Olbiopolitans against the Tauro-Scythians and defeated the latter until they gave hostages to Olbia. The biography names no year, so the event can only be dated to his reign (138–161). Gaidukevich believed that the troops came from Lower Moesia and fought together with the Olbian garrison. The same chapter reports that Antoninus heard a dispute between the Bosporan king Rhoemetalces and an imperial commissioner and sent the king back to his kingdom.

In the 2nd century a Roman garrison was stationed in Olbia, and at the beginning of the 3rd century the city was attached to the province of Lower Moesia. Roman troops also held Chersonesus, their base in Crimea, until the middle of the 3rd century.