Rome at War

An extract from ‘The early Empire’

The expansion of the Empire

Augustus’ immediate successors in the Julio-Claudian dynasty carried on his work of internal pacification and consolidation with occasional external activities. The handover provoked mutinies in the armies of the Rhine and Danube, who were discontented by the longer service which had been introduced after Varus’ disaster but also concerned that only Augustus could guarantee the terms and conditions which they had enjoyed; in each case rapid action defused the situation and the leading mutineers were abandoned to their punishments, which in one legion involved decimation, the killing by their former colleagues of one man in every ten. Under Tiberius (AD 14–37) there were substantial revolts in the Balkans and Gaul, while in Africa, the only part of the Empire where the Senate was still responsible for selecting the commander of a provincial army, a native uprising proved difficult to quash; in the East the annexation of client kingdoms continued with the transformation of Cappadocia into a province, while Armenia was temporarily reduced to a protectorate. Claudius (AD 41–54) oversaw the integration of Thrace and North Africa into the Empire and the continuing assertion of Roman authority over the tribes along the Rhine, but the greatest achievement of his reign was the initiation of the long-delayed conquest of Britain. Claudius himself, a thoroughly unmilitary man, travelled north to be present at the moment of symbolic victory. Nero (AD 54–68), another ruler with little taste for military endeavour, had to confront challenges in Armenia where the Parthians attempted to reassert control; Britain, where harsh methods of tax-gathering and other consequences of annexation provoked Boudicca’s uprising; and Judaea, a province where religion intensified the standard grounds for complaint found in other relatively new provinces. In each case Nero was fortunate to have good commanders to overcome the threats, Corbulo in Armenia, Paulinus in Britain and Vespasian in Judaea, but his own lack of interest in the armies meant that few were prepared to defend him when his unpopularity with the Senate led to challenges to his rule.

The Year of the Four Emperors (68–69) revealed to legions as well as senators what Tacitus described as a ‘secret of imperial rule’: that emperors could be created outside Rome. Galba with support from Spain, next Otho with the backing of the Praetorian Guard at Rome, and then Vitellius with the legions he commanded in upper Germany all briefly fought their way to power, but it was Vespasian, commander of the largest army group in the Empire at the time, who triumphed; the support of the Danubian legions, which had supplied many detachments for the army assembled in Judaea to deal with the Jewish revolt, gave him an overwhelming advantage. Ironically Vespasian had been chosen as commander of this powerful force because Nero had reckoned that his undistinguished background in provincial Italy meant that he could not pose a serious political threat. Vespasian’s position was legitimated, retrospectively, by a senatorial decree which sanctioned all his actions since the day on which his rebellious troops had acclaimed him as emperor.

The new Flavian dynasty (AD 70–96) inaugurated by Vespasian faced similar problems to those of the previous dynasty. The Jewish Revolt was eventually crushed and the Temple of Jerusalem destroyed, the annexation of Britain was advanced with campaigns pushing up into north-eastern Scotland, the process of taking over client kingdoms in the East continued with the annexation of Commagene, and the pressure of German tribes on the upper Rhine and Danube was relieved by the creation of a new frontier to cut off the re-entrant angle between the two rivers. Success, however, bred further challenges and Domitian (81–96) found the Dacians beyond the lower Danube, united under the inspirational leadership of Decebalus, impossible to subdue. Trajan (97–117) inherited the challenges. He was, after Augustus, the greatest conqueror and empire-builder of Roman rulers, and for most of his reign he was personally engaged in expansionist campaigns. In North Africa he pushed Roman authority south to the Aures mountains, a considerable achievement but one which was promptly eclipsed by his activities elsewhere. Between 101 and 107 he campaigned repeatedly beyond the Danube, which was crossed by a long pontoon bridge, first forcing Decebalus to capitulate and then, after a failed rebellion, cornering him so that he committed suicide. A substantial new province, roughly the area of modern Romania, was established. On the eastern frontier, the client Nabataean kingdom was annexed to create the province of Arabia, and then further north Trajan crossed the Euphrates to re-impose Roman authority over Armenia, established a new province of Mesopotamia and finally campaigned down the Tigris to capture the Parthian capital of Seleucia. Trajan may have been inspired by dreams of emulating Alexander the Great, but the diversion of substantial military resources to the eastern provinces had provided opportunities for rebellions elsewhere; even before his death the eastern expansion was looking shaky and thereafter Mesopotamia was promptly abandoned.

Trajan’s two successors, Hadrian (117–138) and Antoninus Pius (138–161), though both competent commanders, pursued a policy of cautious consolidation. This is epitomised most solidly by their respective walls in north Britain, the stone-built Hadrian’s Wall which ran from the Tyne to the Solway and the turf Antonine Wall which blocked the Forth-Clyde neck. Comparable though less monumental works were undertaken in southern Germany and along parts of the frontier in North Africa. At the same time there were internal revolts, most seriously in Judaea where up to half a million provincials may have perished in the restoration of Roman authority and the religious centre of Jerusalem was transformed into a standard Roman colony called Aelia Capitolina.

One feature of the imperial succession in the second century was that emperors did not have sons to succeed them; instead they adopted individuals of proven talent. This process culminated in the reign of Marcus Aurelius (161–180), whom Hadrian had required his immediate successor Antoninus to adopt, in order to arrange the succession at one remove. Marcus Aurelius is regarded by many as the best Roman emperor, partly it is true because he was a reflective intellectual whose introspective Meditations appeal to modern minds, and it was from his reign that Gibbon chose to measure the ‘Decline and Fall of the Roman Empire’. In spite of his philosophical preferences Marcus had to spend much of his reign on campaign. There was the usual round of provincial unrest with Egypt and Mauretania being affected, but a Parthian invasion of Syria reignited hostilities on the eastern frontier; the Romans, under the command of Marcus’ co-emperor Lucius Verus, were successful and re-established a province in Mesopotamia. Much more serious were the various tribal threats to the upper Danube, where Marcus had to spend most of his last decade resisting incursions by the Marcomanni, Quadi and Sarmatians, all of whom were under pressure from Gothic groups which had been shuffling southwards from near the Baltic towards the Black Sea and Danube.

Marcus’ death broke the habit of adoptive succession since he had a son, Commodus (180–192). Although he acquired the reputation of a playboy emperor, who could not stomach the hard work of ruling and preferred to cut deals with enemies rather than fight, his reign witnessed continuing campaigns along the Danube. It was not lack of action which led to his downfall but the failure of his praetorian prefect to ensure that legions received their pay on time which provoked insurrection. Two years of civil war were won by the commander of the largest and toughest army group in the Empire, the Danubian legions, and Septimius Severus (193–211) established a new dynasty. Internal strife inevitably created problems on frontiers, with units being withdrawn for action against fellow Romans, and the protracted campaigns won by Septimius were no exception. In the East, where he had defeated Pescennius Niger and the Syrian legions, not only were substantial cities such as Byzantium sacked but the balance along the frontier had been upset; here Septimius achieved some victories but chose not to extend Roman territory, relying instead on the construction of a client kingdom of Osrhoene based on Edessa (Urfa). At the other end of the Empire, in Britain, Septimius’ second main rival, Clodius Albinus, had depleted the garrison to pursue his ambitions and frontier defences were overrun. First there were substantial works of restoration along and around Hadrian’s Wall, after which Septimius spent the last three years of his life beyond the wall in Caledonia. A massive double legionary fort at Carpow on the river Tay and harbour works at Cramond on the Forth suggest that the Romans were intending to stay, and they may have attempted the systematic depopulation of Strathmore beyond the Tay in order to safeguard their presence.

On his deathbed at York Septimius urged his two sons, Caracalla and Geta, ‘to look after the soldiers and ignore the rest’, advice which did not prevent Caracalla from rapidly disposing of his younger co-ruler. The constant campaigning of Septimius continued under his dynastic successors, with Caracalla (211–217) engaged in Britain, the upper Rhine and the East and Severus Alexander (223–235) active in the latter two sectors. Under Severus Alexander there occurred one of the significant shifts which separates Roman imperial history into earlier and later periods. This was when the Arsacid Parthian dynasty was replaced as Rome’s eastern neighbour by the more aggressive Sassanids. His eventual fate also foreshadows the imperial turmoil of the next half-century since inconclusive campaigning on the Rhine prompted soldiers to complain about their leader, who hid behind his mother’s skirt: he was murdered along with his mother Julia Mamaea, to be replaced by the rough soldier Maximinus the Thracian.