Plutarch, Pompey
Bernadotte Perrin, Ed.

34. Then leaving Afranius in charge of Armenia, Pompey himself proceeded against Mithridates,¹ and of necessity passed through the peoples dwelling about the Caucasus mountains. The greatest of these peoples are the Albanians and the Iberians, of whom the Iberians extend to the Moschian mountains and the Euxine Sea, while the Albanians lie to the eastward as far as the Caspian Sea. [2] These latter at first granted Pompey's request for a free passage; but when winter had overtaken his army in their country and it was occupied in celebrating the Roman festival of the Saturnalia, they mustered no less than forty thousand men and made an attack upon it. To do this, they crossed the river Cyrnus, which rises in the Iberian mountains, and receiving the Araxes as it issues from Armenia, empties itself by twelve mouths into the Caspian. [3] Others say that the Araxes makes no junction with this stream, but takes a course of its own, and empties itself close by into the same sea. Although Pompey could have opposed the enemy's passage of the river, he suffered them to cross undisturbed; then he attacked them, routed them, and slew great numbers of them. [4] When, however, their king sent envoys and begged for mercy, Pompey condoned his wrong-doing and made a treaty with him; then he marched against the Iberians, who were not less numerous than the others and more warlike, and had a strong desire to gratify Mithridates by repulsing Pompey. [5] For the Iberians had not been subject either to the Medes or the Persians, and they escaped the Macedonian dominion also, since Alexander departed from Hyrcania in haste. Notwithstanding, Pompey routed this people also in a great battle, in which nine thousand of them were slain and more than ten thousand taken prisoners; then he invaded Colchis, where, at the river Phasis, Servilius met him, at the head of the fleet with which he was guarding the Euxine.