The Persian Immortals

"The rule in playing chess is to try and see more into guarding your own pieces rather than in taking your opponents’, and not to play bad moves in hope and avarice of taking their pieces, and to keep in mind the count of yours so that you may put one to work and another to care, and to always pay attention to the game principium and be conscious of the end-game."
-- Mâdigân-î Chatrang (Enchiridion of Chess); a sixth century Persian chess guide-book