Some (pseudo-Orpheus) supposed that the Argonauts had sailed up the river Tanais, passed into another river, and by it reached the North Sea, returning to the Mediterranean by the Pillars of Hercules.
These tribes raised wheat, presumably in the river valleys, and sold it for export; in the eastern half from west to east were Georgi (perhaps the same as Aroteres) between the Ingul and the Borysthenes (Dnieper), nomad Scyths and Royal Scyths between the Borysthenes and the Tanais (Don).
We know that in the 2nd century A.D., when the steppes were dominated by the Sarmatae, the majority of the barbarian names in the inscriptions of Olbia, Tanais, and Panticapaeum were Iranian, and can infer that the Sarmatae spoke an Iranian language.
Henceforward the Scyths appear as a declining power: by the middle of the 4th century their eastern neighbours the Sarmatae have crossed the Tanais (Don) and the pressure of the Scyths is felt on the Danube.
The application of the name Tanais to the Syr seems to indicate a real confusion with Colchian Caucasus.