History…is indeed little more than the register of the crimes, follies, and misfortunes of mankind.
Corruption, the most infallible symptom of consitutional liberty.
The terror of the Roman arms added weight and dignity to the moderation of the emperors. They preserved peace by a constant preparation for war; and while justice regulated their conduct, they announced to the nations on their confines, that they were as little disposed to endure, as to offer an injury.
But the zeal of fanaticism prevailed over the cold and feeble efforts of policy.
The situation of the Greeks was very different from that of the barbarians. The former had been long since civilized and corrupted. They had too much taste to relinquish their language, and too much vanity to adopt any foreign institutions. Still preserving the prejudices, after they had lost the virtues, of their ancestors, they affected to despise the unpolished manners of the Roman conquerors, whilst they were compelled to respect their superior wisdom and power.
Augustus was sensible that mankind is governed by names; nor was he deceived in his expectation, that the senate and people would submit to slavery, provided they were respectfully assured that they still enjoyed their ancient freedom.
In the various states of society, armies are recruited from very different motives. Barbarians are urged by the love of war; the citizens of a free republic may be prompted by a principle of duty; the subjects, or at least the nobles, of a monarchy, are animated by a sentiment of honor; but the timid and luxurious inhabitants of a declining empire must be allured into the service by the hopes of profit, or compelled by the dread of punishment.
The general peace which [Constantine] maintained during the last fourteen years of his reign, was a period of apparent splendour rather than of real prosperity; and the old age of Constantine was disgraced by the opposite yet reconcilable vices of rapaciousness and prodigality.
Edward Gibbon - The Decline and Fall of the Roman Empire