History of the Peloponnesian War

While they were yet closing in battle, King Agis resolved to execute a manoeuvre, as follows. All armies, on going into battle, are forced out too much on their right wing; because the men, in their fear, each shelter, as far as possible, their exposed side with the shield of the man who is posted next to them on the right, and think that the closer they are locked together, the more effectually they are protected. The man who primarily gives occasion to this is he who stands first on the right wing, through wishing continually to withdraw from the enemy his own unarmed side; and the rest follow him under the influence of the same fear.

And so, on that occasion, the Mantineans reached with their wing far beyond the Sciritae, and the Lacedaemonians and Tegeans farther still beyond the Athenians, inasmuch as their army was larger than theirs.

Agis therefore, being afraid that their left might be surrounded, and thinking that the Mantineans were extending too far beyond it, gave orders for the Sciritae and Brasidean soldiers to advance from their position with a part of their number, and equalize their line to that of the Mantineans; while into the void thus created he ordered Hipponoidas and Aristocles, two of the polemarchs, to move over from the right wing with their lochi, and by throwing themselves into it to fill it up; thinking that their own right would still have an abundance of strength, and that the line opposite the Mantineans would be formed the more firmly.