Of the grandeur and elevation which Rome imparted to war and to man's nature it is superfluous to speak. As in statesmanship, so in war, he who would greatly praise another describes his excellence as Roman, and thinks that all is said. The silver eagle which Caius Marius gave as an ensign to the legions is for once in history the fit emblem of the race that bore it to victory and world-dominion. History by fate or chance added a touch of the supernatural to the action of Marius. The silver eagle announced the empire of the Caesars; the substitution of the _Labarum_ by Constantine heralded its decline. With the emblem of humiliation and peace, the might of Rome sinks, yet throughout the centuries that follow, returns of galvanic life, recollections of its ancient valour--as in Stilicho, Belisarius, Heraclius, and Zimisces[4]--bear far into the Middle Age the dread name of the Roman legion, though the circuit of the eagle's flight, once wide as the ambient air, is then narrowed to a league or two on either side of the Bosphorus. § 2. DEFINITION OF WAR To push the survey further would but add to the instances, without deepening the impression, of the measureless power of the ideal element in war, alike in the history of the great races of the past and of the present. Even the wars which seem most arbitrary and, to the judgment of their contemporaries, purposeless, acquire, upon a deeper scrutiny and in after ages, a profound enough significance. Behind the immediate occasion, trivial or capricious, sordid or grandiose, the destiny of the race, like the Nemesis of Greek Tragedy, advancing relentlessly, pursuing its own far-off and lofty ends, constantly reveals itself.