In the last epoch of the Empire, the same destructive process went on and on, and the succession remained as turbulent and rapidly changing as before. In the time of Valentinian I'S dynasty, there were still numerous generals and others who decided to attempt these violent grasps at the throne. At least ten men made these lunges, all unsuccessfully in the end, but with varying degrees of initial acceptance. The number rises to thirteen if we include three North African troublemakers with ambiguous intentions. And perhaps there were more.
It is evident what an additional drain the struggles to put down all these usurpers must have imposed on the already hopelessly strained resources of imperial manpower and revenue. And it becomes clearer, too, not only why Valentinian 1 was determined to guarantee a peaceful dynastic succession, but why the army and Empire as a whole still persevered with this policy of heredity throughout the long reigns of the incompetent last members of his house.
Moreover, on the question of usurpers, if not on anything else, the Western and Eastern Emperors, who had a common interest in maintaining the dynasty to which both alike belonged, generally managed to work together - it being understood that as long as one lawful Emperor survived in any part of the Roman world, no other could be created without his agreement. This understanding was not, it is true, invariably observed. Nevertheless, as long as Valentinian I'S dynasty still occupied the thrones in West and East, not one of its rivals ever succeeded in ousting its representatives from either one of the two Empires.
All the same, the diversion of Imperial resources necessitated by such civil wars was disastrous. And during the very last years of the West, after the dynasty of the Valentinians had finally vanished, the chaos deepened. By now most of the ostensible rulers were mere figureheads depending on powerful generals, among whom the German Ricimer (456-72) was pre-eminent. Yet these war-lords still did not venture to seize the monarchical title itself - until 476, when the last Western Emperor was removed from Ravenna, and Odoacer became King of Italy.
Contemporary writers, throughout the entire duration of the Empire, were very well aware of the exceptional damage caused by all these rebellions. Ammianus, in particular, declared military rebels the supreme evil. He had a clear and definite sense of the mutual obligations which linked the lawful Emperor to his people, and was profoundly conscious that, if the ruler was not loyally obeyed by his subjects, the entire safety of the Roman world would collapse.
Augustine, too, demanded 'what fury of foreign peoples, what barbarian cruelty, can be compared with the harm done by civil wars?'. And two of the most prominent among the many insurgents, Magnus Maximus (383-8) whose generals killed Gratian, and Eugenius (392-4) whose Master of Soldiers probably murdered Valentinian 11, are bracketed by the poet Claudian as a pair of truly guilty men:
Two tyrants burst upon the western climes,
Their savage bosoms stored with various crimes;
Fierce Britain was to one the native earth:
The other owed to Germany his birth,
A banished, servile wretch: both soiled with guilt:
Alike their hands a master's blood had split.
Yet such a perpetrator or figurehead of a military revolt, while his tenure of power lasted, sometimes controlled a territory of great size. And, very often, there was no lack of people ready to flock to his colours. As the anonymous treatise
On Matters of Warfare
points out, the discontented poor saw no reason at all why they should not change masters and rally to such rebellions.
The disastrous character of those movements was clearly seen by Gibbon, and by the French historian Montesquieu before him. Montesquieu identified this whole process of traitorous usurpations as one of the principal reasons for the downfall of Rome, tracing how, when once the Empire had grown to such vast dimensions, political differences that had earlier been nothing worse than healthy arguments became transformed into deadly civil wars.
2
The People against the Army
We now come to the second cause of the collapse of the Western Roman Empire: the general failure of its armies to perform the tasks that were required of them. For the Roman armies collapsed, in what at first sight seems an unaccountable fashion, before foreign forces which were, in theory, much their inferiors both in numbers and equipment: the sort of enemies that Rome had often encountered before, and had defeated. In fact, faced with recalcitrant public opinion, and an almost total failure of understanding between the army and the people, Rome had allowed its armies to become fatally weakened.
Our chief source of information about the late Roman army is the Record of Official Posts,
Notitia Dignitatum.
This record gives a list of the principal official posts in the Western and Eastern Empires as they existed in the year 395. Moreover, in so far as the military commanders are concerned, it adds particulars of the units which these officers commanded.
This Record of Official Posts is at one and the same time vitally important and thoroughly misleading. According to its statistics, the troops of the combined Empires numbered between 500,000 and 600,000, twice the size of the forces that had efficiently defended the Roman world two centuries earlier. Of this total number of soldiers, the Western Empire possessed slightly less than half - perhaps a little under 250,000, of whom the majority was stationed on or near the Rhine and Danube borders.
Such numbers, by all precedents, should have been far more than enough for the defence of these frontiers against barbarian incursions. For the armies of Rome's barbarian foes were not, for the most part, numerically very large - no larger than those which had been successfully routed in previous epochs. That is to say, the Visigoth Alaric I and the Vandal Gaiseric may have commanded 40,000 and 20,000 warriors respectively, and the Alamannic host in the 360s had perhaps fallen considerably short of 10,000 fighting men.
But when we look more closely into the forces pitted against these invaders, the picture that emerges becomes strangely different. The Roman armies of the epoch were divided into a high-grade field force and a frontier force. The latter was the less mobile of the two, and harder to free for specific military tasks, being concentrated upon local garrison duties and internal security functions. Besides, as we can detect from a law of 428, it was regarded with less respect and esteem than the field force.
Now an inspection of the Record and other sources of information reveals that no less than two-thirds of the entire army of the Western Empire consisted of such frontier troops, units of second-rate quality. Moreover, the field force suffered such heavy casualties in external and civil wars that it had to take over more and more men - perhaps eventually two-thirds of its total strength - from these frontier armies, particularly in the critical areas of North Africa and Gaul, thus gravely diminishing the frontier defences.
Indeed, the pagan historian Zosimus concluded that Constantine the Great, whom he held principally to blame for this weakening of the frontier force, was thereby largely responsible for the downfall of the Roman Empire. Nor did this situation leave the field force in a satisfactory condition, since it had been obliged to fill up its numbers by so many former frontier troops of lesser calibre. Moreover, the field force had other problems too. For example, its formations in North Africa became, in effect, untransferable to other war-zones, even in an emergency, owing to the need to ensure that the grain from the region should not be lost to Rome.
When we turn to the actual numbers of men commanded in battle by the Roman generals of that time, the position looks graver still. Zosimus remarks that a force of 65,000 put into the field by Julian the Apostate was one of the largest of the age. That seems surprising enough. Yet in the next generation, the most numerous body of soldiers ever mustered by Rome's greatest general of the age, Stilicho - against the Ostrogothic invader Radagaisus in 405 - amounted to no more than 30,000 and was perhaps not much above 20,000. A high figure for any Roman fighting army at this time is 15,000, and expeditionary forces were often only a third as large even as that. This is an enormously far cry from the theoretical figures of the Record of Official Posts, and brings us much closer to the realities of the later Roman Empire. The apparent numerical superiority over the German invaders scarcely existed after all.
The fourth-century writer
On Matters of Warfare
expressed anxiety about this situation. He also offered his Emperors, who are probably Valentinian I and his brother, proposals for putting it right - and they are unusually positive proposals at that. What this author wants the rulers to do, among other things, is to save army manpower by increased mechanization. He therefore suggests a whole series of new types of siege-engines and other equipment. His suggestions went unnoticed, having probably been intercepted and pigeon-holed before they reached the Imperial eyes at all. But their anonymous proposer is important, not merely because he believed, unlike most of his contemporaries, that something practical could be done to improve the world, but because he understood clearly that the recruiting situation of the army was disastrous, and that action would have to be taken to remedy this.
But why was the position so disastrous? The terrific attacks on the frontiers were nothing new. But they were, certainly, becoming more and more frequent - largely because of the weakness within, which invited external encroachments.
There can be little doubt that the weaknesses of the late Roman army were largely due to the eventual failure of the Imperial authorities to enforce regular conscription. Since the beginning of the fourth century AD, it had been the main source of recruitment. Valentinian I, the most effective military leader of the age, conscripted strenuously every year, and Theodosius 1 also, at the beginning of his reign, attempted recruitment on a national scale.
But the exempted categories were cripplingly numerous. Hosts of Senators, bureaucrats and clergymen were entitled to avoid the draft; and among other groups who escaped were cooks, bakers and slaves. To draw the rest of the population into the levy, the combing-out process was intensive. Even the men on the Emperor's own very extensive estates found themselves called up. Yet other great landlords proved far less co-operative. They were supposed to furnish army recruits in proportion to the size of their lands. But on many occasions they resisted firmly. Moreover, even if they gave way, they exhibited a strong tendency only to send the men they wanted to get rid of. They objected that the levies were a heavy strain on the rural population, which were depleted both in numbers and morale. And indeed there was much truth in this. For, since the inhabitants of the cities were virtually useless as soldiers, that was where the burden fell - on the small farmers and peasants, between the ages of nineteen and thirty-five.
In view of such resistance to the draft, it very soon became clear that ordinary measures of recruitment were not stringent enough. Regimentation became the order of the day - and that included compulsion to remain in one's father's profession, so that there was a rapidly increasing tendency to force the sons of soldiers or ex-soldiers to become soldiers in their turn.
This doctrine was already enunciated, though not necessarily obeyed, in the early 300s AD; and by the fifth century it had become obligatory, as in civilian jobs. Moreover, the obligation was sternly insisted upon, in so far as the government possessed the power to have its wishes carried out. But the results were still very far from satisfactory.
The Christian philosopher Synesius of Cyrene (Shahhat) declared that what was needed to save the Empire was
a nation in arms.
As before, the writer
On Matters of Warfare
takes a look at the problem, in so far as it affected the Romans. Complaining that there was no sizeable reserve either of recruits or of veterans, he suggested that it might be easier to track down the reluctant and elusive conscripts if shorter terms of service were introduced. Yet his proposal, even if accepted, would only have been a minor palliative at best. For in the Western Empire, where, as we shall see, the social structure manifested strains which almost annihilated patriotic feeling, there seemed no escape from St Ambrose's conclusion that military service had already ceased to be regarded as a common obligation at all, and was considered merely a servitude - which everyone tried to evade. Universal liability to service could no longer be enforced.
As the frontiers drew in, the provision of soldiers fell more and more upon Italy itself. But the Italians were not able to bear the burden, and had not the slightest intention of doing so. A law of 403 implies that an annual levy still existed at that time. But two enactments of 440 and 443 suggest that, by then, call-ups of recruits in the West were already restricted to emergency occasions only. Indeed, Valentinian m, the author of these edicts, pronounced that 'no Roman citizen shall be compelled to serve', except for the defence of his own town if its safety is endangered. And after the death of the vigorous Aetius, we hear no more of Western citizen recruitment at all.
The senatorial aristocracy, who in this final period dominated the civil administration, was most unlikely to support any such drain on its diminishing agricultural labour. The government, however, had long since drawn one conclusion from this critical state of affairs. If it could not extract recruits from the landowners, then it would extort money from them instead.
Throughout the latter part of the fourth century, therefore, steps were already being taken to explore this alternative. Finally, Senators were formally given the option of paying 25 gold coins in lieu of each missing recruit for whom they were liable. Similarly, individuals could pay cash to escape their own call-ups. The historian Ammianus had already condemned such commuting of service. But, although acceptance of failure, it made a sort of sense once that failure was inevitable. For it proved so hopelessly difficult to secure an adequate number of citizen recruits, even by conscription, that the money would at least ensure that the services of German soldiers could be purchased in their place. And indeed it was to secure their services as fighters that one Emperor after another had permitted them to settle in the provinces as federates and allies. If the West could not have a Roman army, it would have a German force instead. And meanwhile the
Roman
army faded away completely, so that by the time of the Western Empire's final eclipse there was nothing left of it at all.