In the eighteenth century the singular work of the mild and amiable enthusiast, the Abbé de Saint-Pierre,[10] made a profound impression upon the thought not only of his own but of succeeding generations. Kings, princes, philosophers, sat in informal conference debating the same argument as has recently occupied the dignitaries at The Hague. It inspired some of the most earnest pages of D'Alembert and of the Encyclopédie. It drew from Voltaire some happy invective, affording the opportunity of airing once more his well-loved but worthless paradox on the trivial causes from which the great actions of history arise. Saint-Pierre's ideal informs the early chapters of Gibbon's History, but its influence disappears as the work advances. It charmed the fancy of Rousseau, and, by a curious irony, he inflamed by his impassioned argument that war for freedom which is to the undying glory of France.[11] Frederick the Great in his extreme age wrote to Voltaire: "Running over the pages of history I see that ten years never pass without a war. This intermittent fever may have moments of respite, but cease, never!" This is the last word of the eighteenth century upon the dream of Universal Peace--a word spoken by one of the greatest of kings, looking out with dying eyes upon a world about to close in one of the deadliest yet most heroic and memorable conflicts set down in the annals of our race. The Hundred Days are its epilogue--the war of twenty-five years ending in that great manner! Then, like a pallid dawn, the ideal once more arises. Congress after congress meets in ornamental debate, till six can be reckoned, or even seven, culminating in the recent conference at The Hague. Its derisive results, closing the debate of the nineteenth, as Frederick's words sum the debate of the eighteenth century, are too fresh in all men's memories to require a syllable of comment.