Quote by Marcus Aurelius: “The happiness of your life depends upon the quality of your thoughts.”

Your outer circumstances don't determine whether you suffer or flourish — your inner interpretation does. If your default thoughts are fearful, resentful, or bitter, no amount of good fortune will make you happy. The Stoics believed the mind is the only territory you truly control.

Marcus Aurelius wrote the Meditations while commanding Roman armies on the Danube frontier during the Marcomannic Wars. The Roman Empire was under enormous military and economic strain, and plague had swept through much of the population — making his philosophical reflections on equanimity especially significant.

Roman emperor from 161 to 180 CE and Stoic philosopher whose private journal, published posthumously as Meditations, is one of the most widely read works of philosophy in history. He ruled during near-constant military conflict on Rome's borders and personal tragedies within his family.