The following text discusses Stoicism. Stoicism, an ancient Greek school of philosophy founded at Athens by Zeno of Citium, teaches that virtue, the highest good, is based on knowledge; the wise live in harmony with the divine Reason (also identified with Fate and Providence) that governs nature, and are indifferent to the vicissitudes of fortune and to pleasure and pain. Thus, the key to a good life is not in altering external circumstances, but in mastering one’s internal response to them.