Commodus (161-192) was born in 161 and was son of Emperor Marcus Aurelius. At 15 years old, Commodus become co-emperor with his father in 177, making Marcus Aurelius the first emperor to have a legitimate biological heir since Vespasian. He became sole emperor three years later, when his father died in 180. One of his first acts was to devalue the Roman currecy, the largest reduction since Nero's reign. Unlike his father's reign of almost continuous warfare, Commodus ruled over a relatively peaceful Empire, though it was marked by political strife and increasingly megalomaniacal behaviour by Commodus himself. Roman historian Dio Cassius stated that Commodus' reign marked the decline 'from a kingdom of gold to one of iron and rust', with many claiming that Commodus' terrible rule began the decline of the Roman Empire. Commodus was extremely proud of his physical prowess, and often compared himself to Hercules, seeing himself as a reincarnation of the demigod. He also sometimes fought in