Nerva, who ruled from 96 to 98, adopted a generally lavish and liberal policy, but it failed to win the soldiers over completely, and he proved unable to save all Domitian’s murderers from their vengeance. Unrest subsided only when, overlooking kinsmen of his own, he adopted an outstanding soldier, Marcus Ulpius Trajanus, who was governor of Upper Germany, as his successor. Nerva himself died a few months later.
Trajan (ruled 98–117) was the first and perhaps the only emperor to be adopted by a predecessor totally unrelated to him by either birth or marriage. He was also the first in a series of “good” rulers who succeeded one another by adoption and for most of the 2nd century provided the empire with internal harmony and careful government; they are collectively, if somewhat loosely, called the Antonine emperors. More significantly still, Trajan, a Spaniard, was also the first princeps to come from the provinces; with the greater number of provincials now in the Senate, the elevation of one of them, sooner or later, was practically inevitable. Throughout his reign, Trajan generally observed constitutional practices. Mindful of the susceptibilities of the Senate, he regularly consulted and reported to it. Modest in his bearing, he did not claim ostentatious honours such as frequent consulships or numerous imperial salutations, and he mixed easily with senators on terms of cordial friendship. This reestablished mutual respect between princeps and Senate. Empire and liberty, in Tacitus’ words, were reconciled, and the atmosphere of suspicion, intrigue, and terror surrounding the court in Domitian’s day disappeared. Trajan endeared himself also to the populace at large with lavish building programs, gladiatorial games, and public distributions of money. Above all, he was popular with the armed forces; he was the soldier-emperor par excellence. Understandably, he received the title Optimus (Best), officially from 114 on (and unofficially for many years earlier).
Yet Trajan was a thoroughgoing autocrat who intervened without hesitation or scruple even in the senatorial sphere, whenever it seemed necessary. His aim was efficiency; his desire was to promote public welfare everywhere. He embellished Rome with splendid and substantial structures, and he showed his care for Italy by refurbishing and enlarging the harbours at Ostia, Centumcellae, and Ancona. He sent officials called curatores to Italian municipalities in financial difficulties and helped to rehabilitate them. He greatly expanded an ingenious charity scheme probably begun by Nerva: money was loaned to farmers on easy terms, and the low interest they paid went into a special fund for supporting indigent children. Nor did Trajan neglect Italy’s highway network: he built a new road (Via Traiana) that soon replaced the Via Appia as the main thoroughfare between Beneventum and Brundisium.
Interest in Italy implied no neglect of the provinces. Curatores were also sent to them; to rescue Achaea and Bithynia, senatorial provinces, from threatened bankruptcy, Trajan made them both temporarily imperial, sending special commissioners of his own to them. His correspondence with his appointee in Bithynia, the younger Pliny, has survived and reveals how conscientiously the emperor responded on even the smallest details. At the same time, it reveals how limited was access to the central government and, consequently, how great a latitude for independent decisions must be left to the governors who lacked some special claim on the emperor’s attention. Trajan’s day was too short to hear every speech of every delegation from the provinces, every recommendation to bestow favour or grant promotion, and every appeal to himself as supreme judiciary. To assist him, he had a “bureaucracy” of only a few hundred in Rome and a few more hundred serving in various capacities in the provinces—to direct the lives of some 60 million people. Clearly, most government must in fact rest in the hands of local aristocracies.
In the military sphere, Trajan’s reign proved a most dynamic one. He decided to strengthen the dangerous Danube frontier by converting Dacia into a salient of Roman territory north of the river in order to dismember the Sarmatian tribes and remove the risk of large, hostile combinations to a safer distance. Bringing to bear a force of 100,000 men, he conquered Decebalus in two hard-fought wars (101–102; 105–106) and annexed Dacia, settling it with people from neighbouring parts of the empire. On the eastern frontier he planned a similar operation, evidently in the conviction, shared by many eminent Romans both before and after him, that only conquest could solve the Parthian problem. Possibly, too, he wished to contain the menace of the Sarmatian Alani in the Caspian region. In a preliminary move, the Nabataean kingdom of Arabia Petraea was annexed in 105–106. Then, in 114, Trajan assembled another large army, incorporated the client kingdom of Armenia, and invaded Parthia.
After spectacular victories in 115 and 116, he created additional provinces (Northern Mesopotamia, Assyria) and reached the Persian Gulf. But he had merely overrun Mesopotamia; he had not consolidated it, and, as his army passed, revolts broke out in its rear. The Jews of the Diaspora and others seized their chance to rebel, and before the end of 116 much of the Middle East besides Parthia was in arms (Cyrene, Egypt, Cyprus, Anatolia). Trajan proceeded resolutely to restore the situation, but death found him still in the East.
Before his last illness he had not formally indicated his successor. But high honours and important posts had been accorded his nearest male relative, Publius Aelius Hadrianus, the governor of Syria; and, according to Trajan’s widow, Hadrian had actually been adopted by Trajan on his deathbed. Accordingly, both Senate and soldiers recognized him. Trajan’s posthumous deification was never in doubt. Hadrian and the other Antonine emperors
Hadrian (ruled 117–138), also a Spaniard, was an emperor of unusual versatility. Unlike Trajan, he was opposed to territorial expansion. Being himself in the East in 117, he renounced Trajan’s conquests there immediately and contemplated evacuating Dacia as well. Furthermore, four of the consular generals particularly identified with Trajan’s military ventures were arrested and executed “for conspiracy”; Hadrian claimed later that the Senate ordered their deaths against his wishes. The only heavy fighting during his generally peaceful reign occurred in Judaea—or Syria Palaestina, as it was thenceforth called—where Bar Kokhba led a furious, if futile, Jewish revolt (132–135) against Hadrian’s conversion of Jerusalem into a Roman colony named Aelia Capitolina.
Roman EmpireThe extent of the Roman Empire in 117 ce.Encyclopædia Britannica, Inc.
Instead of expansion by war, Hadrian sought carefully delimited but well-defended frontiers, with client states beyond them where possible. The frontiers themselves, when not natural barriers, were strongly fortified: in Britain, Hadrian’s Wall, a complex of ditches, mounds, forts, and stone wall, stretched across the island from the Tyne to the Solway; Germany and Raetia had a limes (fortified boundary) running between Mainz on the Rhine and Regensburg on the Danube. Within the frontiers the army was kept at full strength, mostly by local recruiting of legionaries and apparently of auxiliaries, too (so that Vespasian’s system of having the latter serve far from their homelands gradually ceased). Moreover, the tendency for auxiliaries to be assimilated to legionaries continued; even the officers became less distinguishable, because equites now sometimes replaced senators in high posts in the legions. To keep his essentially sedentary army in constant readiness and at peak efficiency (no easy task), Hadrian carried out frequent personal inspections, spending about half his reign in the provinces (121–125; 128–134).
Hadrian also was responsible for significant developments on the civilian side. Under him, equites were no longer required to do military service as an essential step in their career, and many of them were employed in the imperial civil service, more even than under Domitian. By now the formative days of the civil service were over; its bureaucratic phase was beginning, and it offered those equites who had no military aspirations an attractive, purely civilian career. Formal titles now marked the different equestrian grades of dignity: a procurator was vir egregius; an ordinary prefect, vir perfectissimus; a praetorian prefect, vir eminentissimus, the latter title being obviously parallel to the designation vir clarissimus for a senator. Thenceforth, equites replaced freedmen in the imperial household and bureaus, and they even appeared in Hadrian’s imperial council.