Not paying a large, disciplined army of mercenaries as promised is a terrible idea. The army riots, and even in its riot is able to take the city. This is potentially a disaster of extreme proportion, for even in those days Byzantium was a center of the trade of grains and foodstuffs throughout the region. Indeed, the Spartans had seized the city from Athens during the Peloponnesian War precisely to cut off Athens' grain supply; and while Athens later recaptured it, the Spartans are currently in control of it. The Spartan admiral who promised them money decamps from the city on a fishing boat(!), and escapes to a citadel from which he summons reinforcements.
Xenophon, gravely concerned about the future if he allows the army to plunder this city, manages to restore order and to have the whole army fall into ranks in a large square suitable for such a muster. He explains to them that they are in an inferior position to Athens' when it started its war with Sparta, and therefore can expect even worse results if they provoke open war between themselves and the Spartans. He is successful in reining them in using this rhetorical strategy, and he sends messages to the Spartan admiral to explain that the army feels it has been treated unfairly and would like some additional help in provisioning itself for the expedition he wants them to undertake.
Xenophon has done some great things in this story, but this may be the greatest. Bringing a rioting army back to order is not an easy task. He accomplished it, got them to fall into their ranks, and then reasoned with them successfully to restrain them from the impulse to plunder. That is truly impressive to me.
