Notwithstanding this difference in their personal conduct, the general system of Augustus was equally adopted and uniformly pursued by Hadrian and by the two Antonines. They persisted in the design of maintaining the dignity of the empire, without attempting to enlarge its limits. By every honorable expedient they invited the friendship of the barbarians; and endeavored to convince mankind that the Roman power, raised above the temptation of conquest, was actuated only by the love of order and justice. During a long period of forty-three years, their virtuous labors were crowned with success; and if we except a few slight hostilities, that served to exercise the legions of the frontier, the reigns of Hadrian and Antoninus Pius offer the fair prospect of universal peace. The Roman name was revered among the most remote nations of the earth. The fiercest barbarians frequently submitted their differences to the arbitration of the emperor; and we are informed by a contemporary historian that he had seen ambassadors who were refused the honor which they came to solicit of being admitted into the rank of subjects. The terror of the Roman arms added weight and dignity to the moderation of the emperors. They preserved peace by a constant preparation for war; and while justice regulated their conduct, they announced to the nations on their confines, that they were as little disposed to endure, as to offer an injury. The military strength, which it had been sufficient for Hadrian and the elder Antoninus to display, was exerted against the Parthians and the Germans by the emperor Marcus. The hostilities of the barbarians provoked the resentment of that philosophic monarch, and, in the prosecution of a just defence, Marcus and his generals obtained many signal victories, both on the Euphrates and on the Danube. The military establishment of the Roman empire, which thus assured either its tranquillity or success, will now become the proper and important object of our attention.