The principal conquests of the Romans, were achieved under the republic; and the emperors, for the most part, were satisfied with preserving those dominions which had been acquired by the policy of the senate, the active emulation of the senators, and the martial enthusiasm of the people. The seven first centuries were filled with a rapid succession of triumphs; but it was for Augustus, to relinquish the ambitious design of subduing the whole earth, and to introduce moderation into the public councils. He bequeathed a valuable legacy to his successors, the advice of confining the empire within those limits which nature seemed to have placed as its permanent bulwarks and boundaries:—on the west the Atlantic ocean; the Rhine and Danube on the north; the Euphrates on the east; and towards the south the deserts of Africa and Arabia. The first exception to this policy was the conquest of Britain; the second the conquests of Trajan. It was, however, revived by Hadrian; nearly the first measure of whose reign was the resignation of all that emperor’s eastern conquests. The Roman empire, in the time of the Antonines, was about two thousand miles in breadth, from the wall of Antoninus and the northern limits of Dacia, to Mount Atlas and the tropic of Cancer. It extended, in length, more than three thousand miles, from the Western Ocean to the Euphrates; it was situated in the finest part of the temperate zone, between the twenty-fourth and fifty-sixth degrees of northern latitude; and it was supposed to contain above sixteen hundred thousand square miles, for the most part of fertile and well cultivated land. Pius studied the defence of the empire rather than the enlargement of it—a line of policy, which rendered him more serviceable to the commonwealth than the greatest conqueror. Marcus and Lucius (Antonini) made the first division of the empire. At length it was put up to public sale and sold to the highest bidder. It was afterwards arrested in its ruin by Alexander Severus. The fortunes of the empire, after the progress of several successive tyrants, was again restored by the courage, conduct, and extraordinary virtues of Claudius the Second; to whom has been attributed, with every probability of truth, the courage of Trajan, the moderation of Augustus, and the piety of Antoninus.