Antonine rule commenced with the reign of Antoninus Pius (r. 138–161 A.D.) and included those of Marcus Aurelius (r. 161–180 A.D.), Lucius Verus (r. 161–169 A.D.), and Commodus (r. 177–192 A.D.). Their dynasty reflects the connections between wealthy provincial and Italian families. They were successors of Trajan (r. 98–117 A.D.) and Hadrian (r. 117–38 A.D.), both from respectable provincial families in Spain; Hadrian had secured the line with the adoption of Antoninus Pius, who in turn adopted Marcus Aurelius and Lucius Verus.
Antoninus Pius, who was from southern Gaul, restored the status of the Senate without compromising his imperial power. With succession assured, he quietly furthered the centralization of government. In addition to his own knowledge of law, he surrounded himself with a coterie of legal experts. One result of their revision of Roman law was the ruling that a man must be considered innocent until proven guilty. Antoninus Pius was the last emperor to reside permanently in Rome; his reign was relatively peaceful and benevolent. Military campaigns, such as the one that led to the construction of the Antonine wall in Scotland in the 140s A.D., were conducted by imperial legates, not by the emperor in person. Temples were erected in honor of Antoninus and his wife Faustina, in Rome and throughout the provinces, and many statues and portraits of the imperial couple were produced.
After Antoninus’ death, imperial power was for the first time shared between two co-emperors, his adoptive sons Marcus Aurelius and Lucius Verus. Verus waged a successful war against Parthia and captured Ctesiphon, but died early in 169 A.D. The continuing reign of Marcus Aurelius, however, was marked by incessant warfare with the Germanic tribes along the Upper Danube frontier, later known as the Marcomannic Wars (167–175 A.D.). The theme of victory became dominant in official art, as conquests were commemorated by triumphal arches and monumental columns erected in Rome to celebrate the military achievements of the dynasty. The constant campaigns, however, eventually drained imperial revenues.
Marcus Aurelius’ devotion to duty, protecting the frontiers of the empire, was in marked contrast to the behavior of his son, Commodus. In 180 A.D., Commodus abruptly abandoned the campaigns on the German frontier and returned to Rome. There, however, he alienated the Senate by resorting to government by means of favorites and identifying himself with the semi-divine hero Hercules. By the time of his assassination in 192 A.D., Rome was in a chaotic state of affairs.