The ancient Central Eurasian steppes stretched from Manchuria in the east to the Alfold Plain in Hungary and Romania in the west. Steppe pastoral nomads subsisted largely on the dairy products of their animals, such as cheese, yogurt, and cheese curds, supplemented with meat from their animals as well as from hunting. Covering the Pontic and Caspian steppes, Scythia stretched roughly from the Dniester River to the Amu Darya River and perhaps even to the Altai Mountains. The Sarmatians interacted with the Scythians frequently as the Sarmatians nomadized between the Don and Volga rivers, although by the sixth century some had crossed the Don River and found pastures near the Sea of Azov and may have been subject to Scythian dominion. The Xiongnu merged with other disparate pastoral nomads and formed a new confederation known as the Huns, although this may have been what the Xiongnu called themselves.

The two decades of Diocletian's reign saw the re-establishment of political, military and economic stability after half a century of chaos, at the price of a more absolutist monarchy, a greatly expanded army and bureaucracy and a more oppressive tax regime. Probably in 286 or 287, a new feature of the imperial collegiality emerged. Diocletian and Maximian began respectively to use the adjectival epithets Iovius and Herculius, bringing themselves into some sort of relationship with the cognate deities, Jupiter and Hercules. The years 287-90 had also seen important developments in the eastern half of the empire, to which Diocletian had repaired after the appointment of Maximian and perhaps a campaign against the Sarmatians in the autumn, reaching Nicomedia in Bithynia by 20 January 286. Iovius for Diocletian and Galerius, Herculius for Maximian and Constantius, epithets survived in the naming of new provincial divisions in Egypt some years after the end of the first tetrarchy.

During the first half of the first millennium BC, the southern part of Eastern Europe was occupied mainly by peoples of Iranian stock. The main Iranian-speaking peoples of the region were the Scyths and the Sarmatians. The Scythian period fell at the time of the wet sub-Atlantic climate, which was more damp than the present climate of the Ukraine. Although the ancient Persians called all Scyths 'Saca' the population of ancient Scythia was far from being homogeneous, nor were the Scyths themselves a homogeneous people. The data relating to Scythian beliefs and religion that can be drawn from the remarks by Herodotus and from the representations on Scythian toreutic. The northwest Caucasian Scyths were forced to move again and abandon their country, from the advancing Sarmatian Siraces. The earliest 'genuine Scythian' or 'Royal Scythian' remains north of the Black Sea date from the 600 BC, tallies with the data of the expulsion of the Scyths from Western Asia.