Aure'lius, MARCUS (surnamed Antoninus) (121-180 A. D.), often called simply Marcus Aurelius, a Roman emperor and philosopher, the adopted son and successor of Antoninus Pius. He succeeded to the throne in 161. Brought up and instructed by Plutarch's nephew, Sextus, the orator Herodes Atticus and the jurist L. Volusius Mecianus, he had become acquainted with learned men and had formed a great love for the Stoic philosophy. A war with Parthia broke out in the year of his accession and did not terminate till 166. On his return from this struggle he was obliged to turn his attention to the German tribes who were menacing the Roman state. His brother Verus had died, and the sole command of the war devolved on Marcus Aurelius, who prosecuted it with the utmost vigor, compelling the Marcomanni and other tribes to sue for peace. The sedition of the Syrian governor Avidius Cassius, with whom Faustina, the empress, was in treasonable communication, called the emperor from his conquests, but before he reached Asia the rebel was assassinated. Aurelius returned to Rome, after visiting Egypt and Greece, but soon new incursions of the Marcomanni compelled him once more to take the field. He defeated the enemy several times, but his activities had exhausted him and he died in the midst of his wars. His only extant work is the Meditations, which has been translated into most modern languages, and which contains many beautiful passages that are everywhere familiar. Aurelius was one of the best emperors Rome had, although his philosophy and the magnanimity of his character did not restrain him from the persecution of the Christians, whose religious doctrines he was led to believe were subversive of good government.