Of course it's tempting to close one's eyes to history, and instead speculate about the roots of war in some possible animal instinct: as if, like the tiger, we still had to kill to live, or, like the robin redbreast, to defend a nesting territory. But war, organized war, is not a human instinct. It is a highly planned and cooperative form of theft. And that form of theft began 10,000 years ago when the harvesters of wheat accumulated a surplus and the nomads rose out of the desert to rob them of what they themselves could not provide. The evidence for that, we saw, in the walled city of Jericho and its prehistoric tower... That is the beginning of war.
Episode 2: "The Harvest of the Seasons" - The Ascent of Man (1973)