Every great war known to history resolves itself ultimately into the conflict of two ideals. The Cavalier fights in triumph or defeat in a cause not less exalted than that of the Puritan, and Salamis acquires a profounder significance when considered, not from the standpoint of Athens and Themistocles merely, but from the camp of Xerxes, and the ruins of the mighty designs of Cyrus and Hystaspes, an incident which Aeschylus found tragic enough to form a theme for one of his loftiest trilogies.[1] The wars against Pisa and Venice light with intermittent gleams the else sordid annals of Genoa; and through the grandeur and ferocity of a century of war Rome moves to world-empire, and Carthage to a death which throws a lustre over her history, making its least details memorable, investing its merchants with an interest beyond that of princes, and bequeathing to mankind the names of Hamilcar and Hannibal as a strong argument of man's greatness if all other records were to perish. _Qui habet tenam habet bellum_ is but a half-truth. No war was ever waged for material ends only. Territory is a trophy of battle, but the origin of war is rooted in the character, the political genius, the imagination of the race. One of the profoundest of modern investigators in mediaeval history, Dr. Georg Waitz, insists on the attachment of the Teutonic kindred to the soil, and on the measures by which in the primitive constitutions the war-instinct was checked.[2] The observation of Waitz is just, but a change in environment develops the latent qualities of a race. The restless and melancholy surge, the wide and desolate expanse of the North Sea exalted the imagination of the Viking as the desert the imagination of the Arab. Not the cry of "New lands" merely, but the adventurous heart of his race, lured on by the magic of the sea, its receding horizons, its danger and its change, spread the fame and the terror of the Norsemen from the basilicas, the marbles, and the thronging palaces of Byzantium to the solitary homestead set in the English forest-clearing, or in the wastes of Ireland which the zeal of her monasteries was slowly reclaiming. To the glamour of war for its own sake the Crusades brought the transforming power of a new ideal. The cry "_Deus vult!_" at Clermont marks for the whole Teutonic race the final transition from the type of Alaric and Chlodovech, of Cerdic and Hrolf, to that of Godfrey and Tancred, Richard Lion-heart and Saint Louis, from the sagas and the war-songs of the northern skalds to the chivalrous verse of the troubadours, a Bertrand or a Rudel, to the epic narrative of the crusades which transfigures at moments the prose of William of Tyre or of Orderic, of Geoffrey de Vinsauf or of Joinville.