Anabasis

Afterwards, when darkness had come on, Miltocythes the Thracian, with the horsemen under his command, forty in number, and about three hundred Thracian foot-soldiers, deserted to the King.

But Clearchus put himself at the head of the rest of the troops, following out the plan of his previous orders, and they followed; and they reached the first stopping-place,[*](See Xen. Anab. 2.1.3.) and there joined Ariaeus and his army, at about midnight. Then, while they halted under arms in line of battle, the generals and captains had a meeting with Ariaeus; and the two parties—the Greek officers, and Ariaeus together with the highest in rank of his followers—made oath that they would not betray each other and that they would be allies, while the barbarians took an additional pledge to lead the way without treachery.

These oaths they sealed by sacrificing a bull, a boar, and a ram over a shield, the Greeks dipping a sword in the blood and the barbarians a lance.