Edward Gibbon, The Decline and Fall of the Roman Empire, Chp. V:
“The power of the sword is more sensibly felt in an extensive monarchy, than in a small community. It has been calculated by the ablest politicians, that no state, without being soon exhausted, can maintain above the hundredth part of its members in arms and idleness. But although this relative proportion may be uniform, the influence of the army over the rest of the society will vary according to the degree of its positive strength. The advantages of military science and discipline cannot be exerted, unless a proper number of soldiers are united into one body, and actuated by one soul. With a handful of men, such a union would be ineffectual; with an unwieldy host, it would be impracticable; and the powers of the machine would be alike destroyed by the extreme minuteness or the excessive weight of its springs. To illustrate this observation, we need only reflect, that there is no superiority of natural strength, artificial weapons, or acquired skill, which could enable one man to keep in constant subjection one hundred of his fellow-creatures: the tyrant of a single town, or a small district, would soon discover that a hundred armed followers were a weak defence against ten thousand peasants or citizens; but a hundred thousand well-disciplined soldiers will command, with despotic sway, ten millions of subjects; and a body of ten or fifteen thousand guards will strike terror into the most numerous populace that ever crowded the streets of an immense capital. The Praetorian bands, whose licentious fury was the first symptom and cause of the decline of the Roman empire, scarcely amounted to the last-mentioned number. They derived their institution from Augustus. That crafty tyrant, sensible that laws might color, but that arms alone could maintain, his usurped dominion, had gradually formed this powerful body of guards, in constant readiness to protect his person, to awe the senate, and either to prevent or to crush the first motions of rebellion. He distinguished these favored troops by a double pay and superior privileges; but, as their formidable aspect would at once have alarmed and irritated the Roman people, three cohorts only were stationed in the capital, whilst the remainder was dispersed in the adjacent towns of Italy. But after fifty years of peace and servitude, Tiberius ventured on a decisive measure, which forever rivetted the fetters of his country. Under the fair pretences of relieving Italy from the heavy burden of military quarters, and of introducing a stricter discipline among the guards, he assembled them at Rome, in a permanent camp, which was fortified with skilful care, and placed on a commanding situation. “
