States have been thus conquered from abroad, before they gave any signs of internal decay, even in the midst of prosperity, and in the period of their greatest ardour for national objects. Athens, in the height of her ambition, and of her glory, received a fatal wound, in striving to extend her maritime power beyond the Grecian seas. And nations of every description, formidable by their rude ferocity, respected for their discipline and military experience, when advancing, as well as when declining, in their strength, fell a prey by turns to the ambition and arrogant spirit of the Romans. Such examples may excite and alarm the jealousy and caution of states; the presence of similar dangers may exercise the talents of politicians and statesmen; but mere reverses of fortune are the common materials of history, and must long since have ceased to create our surprise. Did we find, that nations advancing from small beginnings, and arrived at the possession of arts which lead to dominion, became secure of their advantages, in proportion as they were qualified to gain them; that they proceeded in a course of uninterrupted felicity, till they were broke by external calamities; and that they retained their force, till a more fortunate or vigorous power arose to depress them; the subject in speculation could not be attended with many difficulties, nor give rise to many reflections. But when we observe, among many nations, a kind of spontaneous return to obscurity and weakness; when, in spite of perpetual admonitions of the danger they run, they suffer themselves to be subdued, in one period, by powers which could not have entered into competition with them in a former, and by forces which they had often baffled and despised, the subject becomes more curious, and its explanation more difficult.