who taught that governments should be ruled by philosopher-kings
Philosopher king According to Plato, a philosopher king is a ruler who possesses both a love of knowledge, as well as intelligence, reliability, and a willingness to live a simple life. Such are the rulers of his utopian city Kallipolis. For such a community to ever come into being, "philosophers [must] become kings…or those now called kings [must]…genuinely and adequately philosophize" (The Republic, 5.473d).