Marcus Aurelius was a Roman emperor who ruled from 161 to 180 CE and is considered one of the most important Stoic philosophers. He is best known for his work "Meditations," a series of personal writings on Stoic philosophy and self-improvement that continue to be influential today. Despite facing numerous challenges during his reign, including wars and plagues, Marcus Aurelius is remembered as a wise and just ruler who strived to govern according to philosophical principles.