Marcus Aurelius ( or ; Latin: Marcus Aurelius Antoninus Augustus; 26 April 121 – 17 March 180), called the Philosopher, was a Roman emperor from 161 to 180. He ruled the Roman Empire with his adoptive brother Lucius Verus (who took Verus as a regnal name) until Lucius' death in 169. He was the last of the rulers traditionally known as the Five Good Emperors. He is also seen as the last emperor of the Pax Romana, an age of relative peace and stability for the Empire. His personal philosophical writings, now commonly known as Meditations, are a significant source of the modern understanding of ancient Stoic philosophy. They have been praised by fellow writers, philosophers, and monarchs – as well as by poets and politicians – centuries after his death.