Genuine Roman Silver Coin depicting the Emperor Antoninus Pius
Hadrian's heir, Lucius Caesar, died at eighteen. However, since Marcus Aurelius was too young, he was replaced by Antoninus Pius, whom Hadrian had forced to adopt Marcus.
Marcus Aurelius was not happy about leaving the villa where he lived with his widowed mother to move to Hadrian's palace. Since he had no lust for power he felt this as vanity, and later as responsibility.
Born into a senatorial family, Antoninus held various offices during the reign of Emperor Hadrian, who adopted him as his son and successor shortly before his death. Antoninus acquired the cognomen Pius after he acceded to the throne, either because he compelled the Senate to deify his adoptive father, or because he had saved senators sentenced to death by Hadrian in his later years. His reign is notable for the peaceful state of the Empire, with no major revolts or military incursions during this time, and for his governing without ever leaving Italy. A successful military campaign in southern Scotland early in his reign resulted in the construction of the Antonine Wall. Antoninus was an effective administrator, leaving his successors a large surplus in the treasury, expanding free access to drinking water throughout the Empire, encouraging legal conformity, and facilitating the enfranchisement of freed slaves. He died of illness in 161 and was succeeded by his adopted sons Marcus Aurelius and Lucius Verus as co-emperors.