Thucydides (460-400 BCE)
“The best and safest thing of all is when a large force is so well disciplined that it seems to be acting like one man.”
- History of the Peloponnesian War (Book II, section 11) by Thucydides, translated by Rex Warner (Penguin Classics, 1972). The quote comes from a speech that Thucydides wrote while in the character of the Spartan king, Archidamus.