Plutarch, Pompey
Bernadotte Perrin, Ed.

35. Now, the pursuit of Mithridates, who had thrown himself among the peoples about the Bosporus and the Maeotic Sea, was attended with great difficulties; besides, word was brought to Pompey that the Albanians had again revolted. Turning back against these in resentment and wrath, he crossed the Cyrnus again with great difficulty and hazard, since the Barbarians had fenced off its banks with long stretches of palisades; [2] then, since he must make a long march through a waterless and difficult country, he ordered ten thousand skins to be filled with water, and with this provision advanced upon the enemy. He found them drawn up on the river Abas, sixty thousand foot and twelve thousand horse, but wretchedly armed, and clad for the most part in the skins of wild beasts. They were led by a brother of the king, named Cosis, [3] who, as soon as the fighting was at close quarters, rushed upon Pompey himself and smote him with a javelin on the fold of his breastplate; but Pompey ran him through the body and killed him.

In this battle it is said that there were also Amazons fighting on the side of the Barbarians, and that they came down from the mountains about the river Thermodon. For when the Romans were despoiling the Barbarians after the battle, they came upon Amazonian shields and buskins; but no body of a woman was seen. [4] The Amazons inhabit the parts of the Caucasus mountains that reach down to the Hyrcanian Sea, and they do not border on the Albani, but Gelae and Leges dwell between. With these peoples, who meet them by the river Thermodon, they consort for two months every year; then they go away and live by themselves.