On his first entrance into the service, an oath was administered to a private soldier with every circumstance of solemnity. He promised never to desert his standard, to submit his own will to the commands of his leaders, and to sacrifice his life for the safety of the emperor and the empire. The attachment of the Roman troops to their standards was inspired by the united influence of religion and of honor. The golden eagle, which glittered in the front of the legion, was the object of their fondest devotion; nor was it esteemed less impious than it was ignominious, to abandon that sacred ensign in the hour of danger. These motives, which derived their strength from the imagination, were enforced by fears and hopes of a more substantial kind. Regular pay, occasional donatives, and a stated recompense, after the appointed term of service, elevated the hardships of the military life, whilst, on the other hand, it was impossible for cowardice or disobedience to escape the severest punishment. The centurions were authorized to chastise with blows, the generals had a right to punish with death; and it was an inflexible maxim of Roman discipline that a good soldier should dread his officers far more than the enemy. From such laudable arts did the valor of the imperial troops receive a degree of firmness and docility, unattainable by the impetuous and irregular passions of barbarians.

From Edward Gibbon’s The Decline and Fall of the Roman Empire, London: Wordsworth, 1998 (first published from 1776 to 1788), p. 10.