In a.d. 370 various bands of Huns began to cross the Volga, which empties into the Caspian Sea on the border between modern Russia and Kazakhstan. This in itself was not an immediate threat to Rome. When Julius Caesar had crossed the Rubicon in 49 b.c. he was about 350 kilometers away from the imperial capital; the Huns crossing the Volga were approximately ten times farther away from central Italy, and more than 2,000 kilometers from the eastern capital in Constantinople. It would be decades before they asserted themselves directly as a first-rank power in the Roman world.
