A principal design of the great roads was to serve the purposes of military communication. It formed an important item of their military policy, which is quite as well worth studying as their municipal. Notwithstanding the pacific professions of the Incas, and the pacific tendency, indeed, of their domestic institutions, they were constantly at war. It was by war that their paltry territory had been gradually enlarged to a powerful empire. When this was achieved, the capital, safe in its central position, was no longer shaken by these military movements, and the country enjoyed, in a great degree, the blessings of tranquillity and order. But, however tranquil at heart, there is not a reign upon record in which the nation was not engaged in war against the barbarous nations on the frontier. Religion furnished a plausible pretext for incessant aggression, and disguised the lust of conquest in the Incas, probably, from their own eyes, as well as from those of their subjects. Like the followers of Mahomet, bearing the sword in one hand and the Koran in the other, the Incas of Peru offered no alternative but the worship of the Sun or war. It is true, their fanaticism--or their policy--showed itself in a milder form than was found in the descendants of the Prophet. Like the great luminary which they adored, they operated by gentleness more potent than violence.52 They sought to soften the hearts of the rude tribes around them, and melt them by acts of condescension and kindness. Far from provoking hostilities, they allowed time for the salutary example of their own institutions to work its effect, trusting that their less civilized neighbors would submit to their sceptre, from a conviction of the blessings it would secure to them. When this course failed, they employed other measures, but still of a pacific character; and endeavored by negotiation, by conciliatory treatment, and by presents to the leading men, to win them over to their dominion. In short, they practised all the arts familiar to the most subtle politician of a civilized land to secure the acquisition of empire. When all these expedients failed, they prepared for war.