Marcus Aurelius was a Roman Emperor and Stoic philosopher who ruled from 161 to 180 AD. He is best known for his Meditations, a collection of philosophical reflections on life, death, and the nature of existence. He was a proponent of Stoic philosophy, which emphasized the importance of living in accordance with nature and virtue. He was a strong believer in the power of reason and self-discipline, and his writings have had a lasting influence on Western thought. He is remembered as one of the most important figures in the history of philosophy and is often referred to as the "philosopher-king".