Hadrian also improved legal administration. He had his expert jurists codify the edictum perpetuum (the set of rules gradually elaborated by the praetors for the interpretation of the law). He also appointed four former consuls to serve as circuit judges in Italy. This brought Italy close to becoming a province; Hadrian’s intent, however, was not to reduce the status of Italy but to make all parts of the empire important. For one part of his realm, he was exceptionally solicitous: he spent much time in Greece and lavishly embellished Athens.
Hadrian maintained good relations with but was never fully trusted by the Senate. His foreign policy seemed to be unheroic, his cosmopolitanism to be un-Roman, and his reforms to encroach on activities traditionally reserved for senators. Moreover, in his last two years he was sometimes capricious and tyrannous. Like Augustus, he had no son of his own and conducted a frustrating search for a successor. After executing his only male blood relative, his grandnephew, in 136, he adopted Lucius Ceionius Commodus, renaming him Lucius Aelius Caesar. The latter, however, died shortly afterward, whereupon Hadrian in 138 chose a wealthy but sonless senator, the 51-year-old Titus Aurelius Antoninus; but, evidently intent on founding a dynasty, he made Antoninus in his turn adopt two youths, 16 and 7 years old, respectively—they are known to history as Marcus Aurelius (the nephew of Antoninus’ wife) and Lucius Verus (the son of Aelius Caesar). When Hadrian died soon thereafter, Antoninus succeeded and induced a reluctant Senate to deify the deceased emperor. According to some, it was this act of filial piety that won for Antoninus his cognomen, Pius.
Antoninus Pius (ruled 138–161) epitomizes the Roman Empire at its cosmopolitan best. He himself was of Gallic origin; his wife was of Spanish origin. For most men his was a reign of quiet prosperity, and the empire under him deserves the praises lavished upon it by the contemporary writer Aelius Aristides. Unlike Hadrian, Antoninus traveled little; he remained in Italy, where in 148 he celebrated the 900th anniversary of Rome. Princeps and Senate were on excellent terms, and coins with the words tranquillitas and concordia on them in Antoninus’ case mean what they say. Other of his coins not unreasonably proclaim felicitas temporum (“the happiness of the times”). Yet raids and rebellions in many of the borderlands (in Britain, Dacia, Mauretania, Egypt, Palaestina, and elsewhere) were danger symptoms, even though to the empire at large they seemed only faraway bad dreams, to use the expression of Aelius Aristides. Antoninus prudently pushed the Hadrianic frontiers forward in Dacia, the Rhineland, and Britain (where the Antonine Wall from the Firth of Forth to the River Clyde became the new boundary) and carefully groomed his heir apparent for his imperial responsibilities.
Marcus Aurelius (ruled 161–180) succeeded the deified Antoninus and more than honoured Hadrian’s intentions by immediately co-opting Lucius Verus as his full co-emperor. Because Verus’ competence was unproved, this excess of zeal was imprudent. Fortunately, Verus left decision making to Marcus. Marcus’ action was also dangerous for another reason; it represented a long step away from imperial unity and portended the ultimate division of the empire into Greek- and Latin-speaking halves. Nor was this the only foreboding development in Marcus’ reign—formidable barbarian assaults were launched against the frontiers, anticipating those that were later to bring about the disintegration of the empire. Marcus himself was a stoic philosopher; his humanistic, if somewhat pessimistic, Meditations reveal how conscientiously he took his duties. Duty called him to war; he responded to the call and spent far more of his reign in the field than had any previous emperor.
At Marcus’ very accession the Parthians turned aggressive, and he sent Verus to defend Roman interests (162). Verus greedily took credit for any victories but left serious fighting to Avidius Cassius and the army of Syria. Cassius succeeded in overrunning Mesopotamia and even took Ctesiphon, the Parthian capital; he was therefore able to conclude a peace that safeguarded Rome’s eastern provinces and client kingdoms (166). In the process, however, his troops became infected with plague, and they carried it back with them to the west with calamitous results. The Danube frontier, already weakened by the dispatch of large detachments to the East, collapsed under barbarian assault. Pressed on from behind by Goths, Vandals, Lombards, and others, the Germanic Marcomanni and Quadi and the Sarmatian Iazyges poured over the river; the Germans actually crossed Raetia, Noricum, and Pannonia to raid northern Italy and besiege Aquileia. Marcus and Verus relieved the city shortly before Verus’ death (169). Then, making Pannonia his pivot of maneuver, Marcus pushed the invaders back; by 175 they were again beyond the Danube. At that moment, however, a false report of Marcus’ death prompted Avidius Cassius, by now in charge of all eastern provinces, to proclaim himself emperor. The news of this challenge undid Marcus’ achievements along the Danube because it took him to the East and reopened the door to barbarian attacks. Fortunately, Cassius was soon murdered, and Marcus could return to central Europe (177). But he had barely restored the frontier again when he died at Vindobona (Vienna) in 180, bequeathing the empire to his son, the 19-year-old Commodus, who had actually been named coemperor three years earlier.
Commodus (ruled 180–192), like Gaius and Nero, the youthful emperors before him, proved incompetent, conceited, and capricious. Fortunately, the frontiers remained intact, thanks to able provincial governors and to barbarian allies, who had been settled along the Danube with land grants and who gave military service in return. But Commodus abandoned Marcus’ scheme for new trans-Danubian provinces, preferring to devote himself to sensual pleasures and especially to the excitements of the arena in Rome, where he posed as Hercules Romanus and forced the Senate to recognize his godhead officially. He left serious business to his favourites, whose ambitions and intrigues led to plots, treason trials, confiscations, and insensate murders. Commodus’ assassination on the last day of 192 terminated a disastrous reign; thus the Antonines, like the Julio-Claudians, had come to an ignominious end. And there was a similar sequel. Commodus’ damnatio memoriae, like Nero’s, was followed by a year of four emperors. The empire in the 2nd century
The century and three-quarters after Augustus’ death brought no fundamental changes to the principate, although so long a lapse of time naturally introduced modifications and shifts of emphasis. By Flavian and Antonine times the principate was accepted universally. For the provinces, a return to the republic was utterly unthinkable; for Rome and Italy, the year 69 served as a grim warning of the chaos to be expected if, in the absence of a princeps, the ambitions of a few powerful individuals obtained unfettered scope. A princeps was clearly a necessity, and people were even prepared to tolerate a bad one, although naturally they always hoped for a good one.
The princeps, moreover, did not have to be chosen any longer from the Julio-Claudians. The great achievement of the Flavians was to reconcile the soldiers and the upper classes everywhere to the idea that others were eligible. The Flavians’ frequent tenure of consulship and censorship invested their family, though not of the highest nobility, with the outward trappings of prestige and the aristocratic appearance of an authentic imperial household. The deification of the first two Flavians contributed to the same end, and so did the disappearance of old republican families that might have outranked the reigning house (by 69 most descendants of the republican nobility had either died of natural causes or been exterminated by imperial persecution). After the Flavians, the newness of a man’s senatorial dignity and the obscurity of his ultimate origin, whether it was Italian or otherwise, no longer forbade his possible elevation. Indeed, Domitian’s successors and even Domitian himself in his last years did not need to enhance their own importance by repeated consulships. The Antonine emperors, like the Julio-Claudians, held the office infrequently. They did, however, continue the Flavian practice of emphasizing the loftiness of their families by deifying deceased relatives (Trajan deified his sister, his niece, and his father; Antoninus, his wife; and so forth). Trend to absolute monarchy