To any one who attentively considers this all-important subject, two things must be apparent, of the very highest consequence in arriving at correct ideas on it. The first is, that the Roman empire did not sink under the external violence of the barbarians, but under the weakness and decline which had arisen in its own bosom. The second, that the causes hitherto assigned by historians and philosophers for this internal decay, are either vague generalities, having no definite meaning, and incapable of any practical application, or can be easily shown, even to the most superficial reader, not to have been the real causes of the phenomenon.
There can be no doubt that some of the irruptions of the barbarians—particularly those of the Goths into Romelia, which led to the fatal battles of Thessalonica and Adrianople; and of Alaric into Italy, which terminated in the capture of the Eternal City—were very formidable inroads, and might, in the best days of the empire, have taxed its strength and resolution to repel. But a little consideration must be sufficient to show, that, formidable as these invasions were, they could without much difficulty have been withstood, if the empire had possessed the strength which it did in the days of the republic, or in the first two centuries of the Cæsars. The Cimbri and Teutones, whom Marius combated and destroyed on the Rhone and in the north of Italy, were at least as formidable a body of barbarians as those which four centuries afterwards overturned the western empire. The forces whom Cæsar conquered in Gaul, Trajan on the Danube, were to the full as powerful as those which carried the standards of the Goths and Vandals to Athens and Carthage. Ætius, in the decline of the empire, and with the mingled Roman and barbarian force of Gaul alone, defeated Attila in the plenitude of his power, at the head of three hundred thousand men, on the field of Chalons.
Belisarius, with fifteen thousand men, recovered Africa from the Vandals; thirty thousand legionary soldiers did the same by Italy under Narses, and overthrew the whole power of the Goths. So high did the Roman soldiers still stand even in the estimation of their enemies, that Totila, the warlike monarch of the Goths, strove to bribe them into his service by offers of high pay. None had yet been approved equal to these legionary soldiers in battle; and the manner in which, with infinitely inferior forces, they repelled the barbarians on all sides, decisively demonstrates this superiority. The vigour and ability of Heraclius so restored the empire, when wellnigh sinking under the might of its enemies, that for a century it was regarded with awe by the barbarous nations all round its immense frontier. The five provinces beyond the Euphrates were conquered by the Romans from the Parthians during the decline of the empire. Nothing is so remarkable, in the last three centuries of Roman history, as the small number of the forces which combated around the Eagles, and the astonishing victories which, when led by ability, they gained over prodigious bodies of their enemies. The legions had dwindled into battalions, the battalions into cohorts. The four hundred and fifty thousand men who under Augustus guarded the frontiers of the empire, had sunk to one hundred and fifty thousand in the time of Justinian.[3] But this hundred and fifty thousand upheld the Eastern empire for a thousand years. So feeble were the assaults of the barbarians, that for above two centuries of that time the single city of Constantinople, with the aid of the Greek fire, defended itself with scarce any territory from which to draw support. It was not the strength of its enemies, therefore, but the weakness of itself, which, after an existence in the West and East of two thousand years, at length extinguished the Roman empire.
What, then, were the causes of decay which proved fatal at length to this immense and enduring dominion? Philosophers in all ages have pondered on the causes; but those hitherto assigned do not seem adequate to explain the phenomenon. Not that the causes of weakness are baseless or imaginary; on the contrary, many of them were most real and substantial sources of evil. But what renders them inadequate to explain the fall of Rome is, that they had all existed, and were in full operation, at the time when the commonwealth and empire were at their highest point of elevation, and centuries before either exhibited any symptoms of lasting decay. For example, the ancient historians, from Sallust downwards, are loud in their denunciation of the corruption of public morals, and the selfish vices of the patrician classes of society, as being the chief source of the decay which was going forward, while the growth of the republic had been mainly owing to the extraordinary virtue and energy of a small number of individuals.[4] But the very circumstance of these complaints having been made by Sallust in the time of Augustus, and the fact of the empire of the West having existed for four hundred, that of the East for fourteen hundred years afterwards, affords decisive evidence that this cause cannot be considered as having been mainly instrumental in producing their fall. How is the unexampled grandeur and prosperity of the empire under Nero, Adrian, Trajan, and the two Antonines, whose united reigns extended over eighty years, to be explained, if the seeds of ruin two centuries before had been sown in the vices and corruption of the rich patricians? In truth, so far was general luxury or corruption from being the cause of the ruin of the empire, the cause of its fall was just the reverse. It was the excessive poverty of its central provinces, and their inability to pay the taxes, which was the immediate cause of the catastrophe. The nobles and patricians often were luxurious, but they were not a thousandth part of the nation. The people was miserably poor, and got more indigent daily, in the later stages of its decay.
Modern writers, to whom the philosophy of history for the first time in the annals of mankind has become known, and who were aware of the important influence of general causes on social prosperity, independent of the agency of individual men, have assigned a different set of causes more nearly approaching the truth. Montesquieu says, the decay of the Roman empire was the natural consequence of its extension. This sounds well, and looks like an aphorism: but if the matter be considered with attention, it will be found that it is vox et præterea nihil. Those who, with so much complacency, rest in the belief that the fall of the Roman empire was the natural result of its extension, forget that its greatest prosperity was coexistent with that very extension. It is impossible to hold that the decay of the empire was the consequence of its magnitude, when the glorious era of the Antonines, during which it numbered a hundred and twenty millions of inhabitants under its rule, and embraced nearly the whole known habitable globe within its dominion, immediately succeeded its greatest extension by the victories, unhappily to us so little known, of Trajan.
More recent writers, seeing that Montesquieu's aphorism was a vague proposition which meant nothing, have gone a step further, and approached much nearer to the real explanation of the phenomenon. Guizot, Sismondi, and Michelet have concurred in assigning as the real cause of the decay of the Roman empire, the prevalence of slavery among its working population, and the great and increasing weight of taxes to support the imperial government. There can be no doubt that these were most powerful causes of weakness; and that they stand prominently forth from the facts recorded by contemporary annalists, as the immediate and visible causes of the decline of the empire. The history of these melancholy periods is full of eternal complaints, that men could not be got to fill the legions, nor taxes to replenish the treasury; that the army had to be recruited from the semi-barbarous tribes on the frontier; and that vast tracts of fertile land in the heart of the empire relapsed into a state of nature, or were devoted only to pasturage, from the impossibility of finding cultivators who either would till the land, or could afford to pay the taxes with which it was charged. Doubtless the large proportion—at least a half, perhaps nearly two-thirds—of the people who were slaves, must have weakened the elements of strength in the empire; and the enormous weight of the direct taxes, so grievously felt and loudly complained of,[ [5] must have paralysed, to a very great degree, both the industry of the people and the resources of government. But a very little consideration must be sufficient to show, that these were not the real sources of the decline of the empire; or rather, that if they had not been aided in their operation by other causes, which truly undermined its strength, it might have been great and flourishing to this hour.
Slavery, it must be recollected, was universal in antiquity, and is so over two-thirds of the human race at this hour. Much as we may feel its evils and deprecate its severities, we ourselves, till within these three centuries, were entirely fed by serfs; and a few years only have elapsed since the whole of our colonial produce was raised by slave labour. America and Russia—the two most rising states in existence—are, the former in part, the latter wholly, maintained by slaves. It was an army, in a great measure composed of men originally serfs, which repelled Napoleon's invasion, survived the horrors of the Moscow retreat, and carried the Russian standards to Paris, Erivan, and Adrianople. Alexander the Great conquered Asia with an army of freemen wholly fed by slaves. The Athenians, in the palmy days of their prosperity, had only 21,000 freemen, and 400,000 slaves. Rome itself, in its great and glorious periods, when it vanquished Hannibal, conquered Gaul, subdued the East—in the days of Scipio, Cæsar, and Trajan—was to the full as dependent on slave labour as it was in those of its decrepitude under Honorius or Justinian. Cato was a great dealer in slaves; the Sabine farm was tilled by the arms of slaves; Cincinnatus and Regulus worked their little freeholds entirely by means of slaves. Rome was brought to the verge of destruction, nearer ruin than it had been by the arms of the Carthaginians, by the insurrection of the slaves shortly after the third Punic contest, so well known under the appellation of the Servile war. It is perfectly ridiculous, therefore, to assign as a cause of the destruction of Rome, a circumstance in the social condition of its people which coexisted with their greatest prosperity, which has prevailed in all the most renowned nations of the earth in a certain stage of their progress, and is to be found, in our own times, in states the most powerful, and the most likely to attain vast and long-continued dominion.
Equally futile is it to point to the weight of the taxes as the main cause of the long decline and final overthrow of Rome. Taxes no doubt are an evil; and if they become excessive, and are levied in a direct form, they may come in the end to ruin industry, and weaken all the public resources to such an extent as to render a nation incapable of defending itself. But a very little consideration must be sufficient to show that it was not, in the case of Rome, the increase of the taxes taken as a whole, but the decline in the resources of those who paid them, which rendered them so oppressive. If, indeed, the national establishment of the Roman empire had gone on increasing as it advanced in years, until at length their charges became excessive and crushing to industry, the theory would have been borne out by the fact, and afforded perhaps satisfactory explanation of the phenomenon. But the fact was just the reverse. The military establishment of the Roman empire was so much contracted as it advanced in years that whereas it amounted to 450,000 men in the days of Augustus, in those of Justinian it had sunk, as already noticed to 150,000.[ [6] So far were the forces of Rome from being excessive in the later stages of the empire or disproportioned to an empire still, after all its losses, holding so large and fair a portion of the earth under its dominion, that on the other hand they were miserably small; and the disasters it underwent were mainly owing to the government of the Cæsars never being able to equip an adequate army to repel the attacks of the barbarians. The force with which Belisarius reconquered Africa and recovered Italy, never mustered seventeen thousand men; and the greater part of his successes were achieved by six thousand legionary followers. It was not the weight of the national establishments, therefore, but the diminished resources of those who were to pay them, which really occasioned the destruction of the empire.
There are two other facts of vital importance in considering the real causes of the gradual decay and ultimate ruin of the dominion of the legions.
The first of these is, that the extent of the decay was, in the latter stages of Rome, very unequal in the different provinces of the empire; and that while the central provinces, and those in the neighbourhood of the metropolis, were in the most wretched state of decrepitude, the remote districts were in the highest state of affluence and prosperity. This important fact is abundantly proved by unquestionable authority, and it sheds a flood of light on the real causes of the ruin which ultimately overtook them all.