Marcus Aurelius Antoninus (121-180 AD) was a Roman emperor and a Stoic philosopher. He was a ruler who deeply valued philosophy and is best known for his Meditations on Stoic philosophy. He rose to power as the emperor of Rome in 161 AD and ruled for nearly two decades until his death in 180AD. He was the last of the rulers known as the Five Good Emperors and the last emperor of the Pax Romana, an age of relative peace and stability for the Roman Empire.