When discord arose, then the two races were drawn different ways; the iron and brass fell to acquiring money and land and houses and gold and silver; but the gold and silver races, having the true riches in their own nature, inclined towards virtue and the ancient order of things. There was a battle between them, and at last they agreed to distribute their land and houses among individual owners; and they enslaved their friends and maintainers, whom they had formerly protected.
— PLATO, The Republic,
Jowett's Translation, Book VIII., p. 547
(Words ascribed to Socrates).