Marcus Aurelius Antoninus was a Roman emperor from 161 to 180 and a Stoic philosopher. He was the last of the rulers known as the Five Good Emperors, and the last emperor of the Pax Romana (27 BC to 180 AD), an age of relative peace and stability for the Roman Empire. He served as Roman consul in 140, 145, and 161. Marcus was born during the reign of Hadrian to the emperor's nephew, the praetor Marcus Annius Verus, and the heiress Domitia Calvilla.