The Roman empire extended from Britain in the north to the Sahara desert in the south. But its principal and most sensitive frontiers were those which stretched for thousands of miles along the Rhine, Danube and Euphrates, and along the borders of a few advanced territories beyond certain sectors of those three great rivers.
At the time with which this book begins, most of the unified state had long been at peace. Augustus (d. AD 14), who had replaced the inadequate government of the Republic by an autocracy elaborately concealed beneath traditional forms, laid a firm basis for the Pax Romana by a thoroughgoing overhaul of the entire administration, which was henceforward able to control the nearly thirty (later nearly fifty) provinces with efficiency, honesty and increasing mildness. The empire’s backward social structure makes it difficult to agree with Gibbon that the human race, in these regions, has never again enjoyed the happiness and prosperity of the second century AD (p.xv). And yet the emperors of that period brought all these peoples the blessing of profound, durable peace, such as had not been seen over so large an area before and has never been seen again.
Although peace brought with it a certain atrophying of originality, the reign of Marcus Aurelius was distinguished by four authors whose gifts show how misleading it is to dismiss this period patronisingly (as is done, for example, by our educational systems) as post-classical. These are the scintillating Latin novelist Apuleius from north Africa, and, among writers in Greek, the razor-sharp, scoffing Lucian from the Euphrates area, Galen from Asia Minor ‘the medical pope of the Middle Ages’, and the emperor himself, whose Meditations reveal one of the most complex and thoughtful men ever to occupy a throne.
And yet it was in the reign of Marcus Aurelius and his fellow-emperor Lucius Verus that the military situation grew sharply and permanently worse, with results which demolished the Roman Peace for ever. A recurrence of the usual expensive military operations against Rome’s eastern neighbour on the Euphrates, Parthia, was followed by threats of a gravity never hitherto experienced from the Teutonic and Iranian tribes, Germans and Sarmatians, who lived beyond the Rhine and Danube. These consequent campaigns, which were accompanied by an epidemic of plague and followed by many further wars during the century to come, are depicted with a new sense of horror and pathos on the Arch of Marcus Aurelius. The fighting cost sums so large that their exaction from the subjects of the empire put an end to the relative comfort and ease of the middle classes. A second factor which contributed substantially to their impoverishment was the recurrence, after well over a century’s intermission, of a constant series of civil wars caused by disputed imperial successions resulting in the assassination of one ruler after another. The death of Marcus’ unconventional, deranged son Commodus (180–92), during whose reign eastern religious tendencies made much headway and gladiatorial games enjoyed imperial participation, was followed by four ruinous years of such warfare, in which the survivor of five claimants to the imperial throne was Septimius Severus (193–211).1 *
Trajan (d. 117), of Romano-Spanish origin, had been the first emperor who was not an Italian, and that was a pointer to the future in which very few rulers came from Italy; the country lost its political and economic importance and became a mere framework for the prestige of eternal, subsidised Rome. Septimius, on the other hand, was the first of a number of non-Europeans, for his homeland was north Africa, which was also the only area still producing a distinguished Latin literature. But his influential wife Julia Domna came from Syria, which, through the medium of its Hellenized writers and artists, contributed an even greater share of the empire’s talents and achievements. Indeed Syrian and other oriental literary, artistic and spiritual themes now began to encroach more and more upon the traditions of Greece and Rome, thereby forming the distinctive amalgam that is characteristic of this later empire. Though Septimius maintained the fiction that he belonged (through adoption by Marcus Aurelius) to the tradition of the Antonine Golden Age, his exceptional ability and clear-sighted ruthlessness qualified him perfectly for the task, in which he was aided by the most famous jurists in legal history, of developing his rule into an absolute autocracy. For there now had to be painful adjustments to a new and grimmer age of intensified, forcibly collected taxation, in kind as well as cash; while people forgot these troubles, when they could, by reading the best of the ancient romantic novelists, Longus and Heliodorus.
Septimius’ neurotically ambitious, boorish son Caracalla (211–17) eliminated his father-in-law, the praetorian prefect,* and then his own brother Geta, but only survived the latter by five years. His successor, Macrinus, was a Mauretanian whose elevation to the throne displayed the growing weakness of the senate, since he was the first emperor not to have been a member of that body. He soon succumbed to the first Syrian to occupy the throne, Elagabalus (218–22), a fourteen-year-old Sun-priest and sexual invert who belonged to the family of Julia Domna. Elagabalus’ attempt to introduce Rome to thoroughgoing religious orientalisation was tactless and premature, and yet under his younger cousin Severus Alexander (222–35), whose mother Julia Mamaea acted as regent, the religious tendencies of the previous reign continued to make headway in less extreme and obtrusive forms. Severus Alexander, unlike his predecessor, tried to appear as a Roman traditionalist who respected the senate. But it was not possible to revert to an old-fashioned constitutionalist régime, since the financial needs of the empire had suddenly become very much greater than they had been before. This was due to the replacement of Rome’s eastern enemy Parthia – the only sizeable political unit on the imperial borders-by a far more dangerous foe, the Sassanian Persians.
The emergence of this major foreign power unhappily coincided with the deterioration of Rome from Military Monarchy into Military Anarchy. For the next half century the empire was almost continuously convulsed by internal wars of succession. Advantage of this weakness was taken both by Persia and by the increasingly formidable German and other tribes operating from beyond the Danube frontier. The huge peasant-born Thracian Maximinus I might have dealt effectively with these latter attacks if he had not handled his own subjects with methods of particular severity which led to his death (238).
In that single year the empire saw the coinage of no fewer than seven Caesars. These included three successive pairs of murdered colleagues, ruling jointly, in pursuance of ancient consular precedents, in order to spread the imperial burden.2 The survivor of the seven was Gordian (238–44), a youth of thirteen whose praetorian prefect Timesitheus became his all-powerful minister. The Persians were now ruled by their most aggressive expansionist, Shapur I; and the empire during the next twenty years also experienced the maximum intensification of German invasions. A series of soldier-emperors, whose careworn faces have come down to us in portrait busts of unrivalled quality, seemed unlikely to be able to save the Roman world. Philip the Arab (244–9) distracted attention by celebrating the millennium of Rome; Decius (249–51) and Valerian (253–60),3 amid pestilence and increasing currency debasement, blamed their catastrophes upon the growing sect of the Christians. These, who had now produced educated apologists in Alexandria and elsewhere, were soon able to show in their turn how Decius was killed in battle against the Germans (Goths) and Valerian suffered the appalling ignominy of capture by the Persians. While these successive, unprecedented blows prompted one Roman general after another to declare himself emperor in the provinces, Valerian’s son, colleague and successor Gallienus (253–68) was confronted by a breakaway of the western provinces under Postumus. Moreover, faced by currency collapse, price inflation and overwhelming attacks on both main fronts –involving the permanent loss of the upper Rhine-Danube re-entrant – Gallienus was also obliged to concede virtual independence to a large eastern princedom under Odenathus of Palmyra. Odenathus’ widow and successor Zenobia conquered all Rome’s oriental provinces; and the emperor of Rome now controlled only the precarious central strip of an empire which seemed to be in full disintegration.
And yet, at an incalculable expense of human resources and human happiness, the long haul towards military recovery had begun. Despite the fearful disasters of his reign – and a dubious reputation as a cultured Hellenist who was not sufficiently anti-Christian – Gallienus started to stem the tide by establishing a new mobile cavalry army with which he apparently won a major victory over the Goths. After him, in a period which witnessed the successive deaths of the two greatest teachers of the age, Plotinus the Platonist and mystic in Campania and Mani founder of the Manichaeans in Persia, three emperors of the Danubian peasant stock which now formed the backbone of the army, Claudius II Gothicus (268–70), Aurelian (270–5) and Probus (276–82), directed almost miraculous feats of strategical skill and endurance which eliminated the menace on the northern frontiers.4
In order to achieve this result, Aurelian took the exceptional step of stabilising his frontier by deliberately and permanently evacuating a province (trans-Danubian Dacia). Yet he brought back under his rule the western and eastern ‘empires’ that had defected. At the same time he sought to revive official paganism, in the face of its Christian and other competitors, on the basis of the Sun-worship which had become an almost monotheistic cult, with the stern faith of Mithraism as its offshoot.
Carus (282–3) restored the situation on the eastern frontier. Then his sons adopted the practice, sometimes resorted to earlier, of dividing the empire on a geographical basis,5 and this arrangement was placed on what was intended to be a permanent basis by Diocletian (284–305). While himself ruling the eastern provinces from Nicomedia (Izmit), he raised Maximian, an Illyrian peasant like himself, to be his co-Augustus in the west, based on Mediolanum (Milan); Rome was no longer an imperial capital. Furthermore, this was to be a Tetrarchy, in which each emperor had an imperial coadjutor intended to be his heir— Galerius in the east, and Constantius I Chlorus in the west.
Diocletian, who combined Roman conservative patriotism with unflinching systematic insight into power-structures and long-term planning, gathered together all the threads which were tending towards absolutism, and formalised his autocratic government with ceremonial reminiscent less of Augustan Rome than of Sassanian Persia. The accompanying hieratic art, too, had moved a long way from classical ideals. It was housed in palaces of unprecedented splendour, architectural originality and expense. Greater cost still fell on the crushingly taxed citizens of the empire when Diocletian’s analysis of imperial obligations caused him not only to institute a large-scale expansion of the civil service but to double the size of the army. The requirements of this huge force were provided by converting the exactions in kind, which had been a feature of the previous century, into a regular system. The methods employed to collect these materials, extortionate though they were, at least showed everyone where they stood, because the empire’s needs were publicly announced each year in the first known annual budgets of history. But Diocletian, confronted like his predecessors with galloping inflation, showed the weakness of the ancient world in economic theory when he failed to control rising prices by his currency reform or his unprecedented edict enforcing maximum prices.
In rapid progression towards a totalitarian state, Diocletian decided to rally the peoples of the empire behind the traditional gods, and his desire to make their worship obligatory led him to the severest of all persecutions of the Christians (303). This outlasted the abdication of Diocletian (305) by eight confused years, during which the Tetrarchy broke down among a welter of joint, competing occupants of the throne.6 But Galerius, who had abetted or instigated Diocletian’s persecutions, called the anti-Christian campaign off from his deathbed (311). Although his successor Maximinus II Daia (d. 313) then undertook a further attempt to reinforce paganism as a counterweight to Christianity, Constantine the Great, hitherto a determined adherent of Sun-worship, declared that his conquest of Italy from Maxentius (312) had been achieved under Christian auspices. Then, intensifying his dedicated, if theologically somewhat muddled, endeavours to Christianise the empire, he transformed the church from a national enemy into a heavily subsidised state religion subordinate to the emperor, with superb new churches for its worship.
Meanwhile Constantine, a man of impetuous, wide-ranging energy who was convinced of his god-sent mission, suppressed his eastern coruler Licinius, and thus became the sole survivor of six rival emperors and the only occupant of the throne (324–37). He completed a massive reorganisation of the army on more mobile lines than hitherto, stabilised all frontiers and still further expanded the bureaucracy. Constantine’s tightening of the authoritarian, autocratic and theocratic state is echoed in the transcendent immobility of his statues, which proclaim the death of humanism.
Since the emperor had to be within reach of the Danube and Euphrates frontiers and the resources of the eastern provinces, which by now far exceeded those of the west, Constantine selected Byzantium on the Bosphorus as his capital, renaming it Constantinople (324–30). After the empire had become permanently partitioned by a north-south line running west of Singidunum (Belgrade) (395), its western regions disintegrated into new German countries and ceased to have their own emperor (476). But the eastern territories, retaining the name of the Roman empire, continued the rule of Rome from Constantinople for nearly a thousand years after the last emperor had ruled in Italy.