History of the Peloponnesian War

But while they were still closing, King Agis resolved to make the following manoeuvre. All armies are apt, on coming together, to thrust out their right wing too much; and both sides extend with their right beyond their opponents' left wing, because in their fear each man brings his uncovered side as close as possible to the shield of the man stationed on his right, thinking that the closer the shields are locked together the better is the protection. And it is the first man on the right wing who is primarily responsible for this, since he always wants to withdraw from the enemy his own uncovered side, and the rest, from a like fear, follow his example.