Happily for the repose of mankind, the moderate system recommended by the wisdom of Augustus, was adopted by the fears and vices of his immediate successors. Engaged in the pursuit of pleasure, or in the exercise of tyranny, the first Caesars seldom showed themselves to the armies, or to the provinces; nor were they disposed to suffer, that those triumphs which their indolence neglected, should be usurped by the conduct and valor of their lieutenants. The military fame of a subject was considered as an insolent invasion of the Imperial prerogative; and it became the duty, as well as interest, of every Roman general, to guard the frontiers intrusted to his care, without aspiring to conquests which might have proved no less fatal to himself than to the vanquished barbarians. 5
The only accession which the Roman empire received, during the first century of the Christian Aera, was the province of Britain. In this single instance, the successors of Caesar and Augustus were persuaded to follow the example of the former, rather than the precept of the latter. The proximity of its situation to the coast of Gaul seemed to invite their arms; the pleasing though doubtful intelligence of a pearl fishery, attracted their avarice; 6 and as Britain was viewed in the light of a distinct and insulated world, the conquest scarcely formed any exception to the general system of continental measures. After a war of about forty years, undertaken by the most stupid, 7 maintained by the most dissolute, and terminated by the most timid of all the emperors, the far greater part of the island submitted to the Roman yoke. 8 The various tribes of Britain possessed valor without conduct, and the love of freedom without the spirit of union. They took up arms with savage fierceness; they laid them down, or turned them against each other, with wild inconsistency; and while they fought singly, they were successively subdued. Neither the fortitude of Caractacus, nor the despair of Boadicea, nor the fanaticism of the Druids, could avert the slavery of their country, or resist the steady progress of the Imperial generals, who maintained the national glory, when the throne was disgraced by the weakest, or the most vicious of mankind. At the very time when Domitian, confined to his palace, felt the terrors which he inspired, his legions, under the command of the virtuous Agricola, defeated the collected force of the Caledonians, at the foot of the Grampian Hills; and his fleets, venturing to explore an unknown and dangerous navigation, displayed the Roman arms round every part of the island. The conquest of Britain was considered as already achieved; and it was the design of Agricola to complete and insure his success, by the easy reduction of Ireland, for which, in his opinion, one legion and a few auxiliaries were sufficient. 9 The western isle might be improved into a valuable possession, and the Britons would wear their chains with the less reluctance, if the prospect and example of freedom were on every side removed from before their eyes.
But the superior merit of Agricola soon occasioned his removal from the government of Britain; and forever disappointed this rational, though extensive scheme of conquest. Before his departure, the prudent general had provided for security as well as for dominion. He had observed, that the island is almost divided into two unequal parts by the opposite gulfs, or, as they are now called, the Friths of Scotland. Across the narrow interval of about forty miles, he had drawn a line of military stations, which was afterwards fortified, in the reign of Antoninus Pius, by a turf rampart, erected on foundations of stone. 10 This wall of Antoninus, at a small distance beyond the modern cities of Edinburgh and Glasgow, was fixed as the limit of the Roman province. The native Caledonians preserved, in the northern extremity of the island, their wild independence, for which they were not less indebted to their poverty than to their valor. Their incursions were frequently repelled and chastised; but their country was never subdued. 11 The masters of the fairest and most wealthy climates of the globe turned with contempt from gloomy hills, assailed by the winter tempest, from lakes concealed in a blue mist, and from cold and lonely heaths, over which the deer of the forest were chased by a troop of naked barbarians. 12
Such was the state of the Roman frontiers, and such the maxims of Imperial policy, from the death of Augustus to the accession of Trajan. That virtuous and active prince had received the education of a soldier, and possessed the talents of a general. 13 The peaceful system of his predecessors was interrupted by scenes of war and conquest; and the legions, after a long interval, beheld a military emperor at their head. The first exploits of Trajan were against the Dacians, the most warlike of men, who dwelt beyond the Danube, and who, during the reign of Domitian, had insulted, with impunity, the Majesty of Rome. 14 To the strength and fierceness of barbarians they added a contempt for life, which was derived from a warm persuasion of the immortality and transmigration of the soul. 15 Decebalus, the Dacian king, approved himself a rival not unworthy of Trajan; nor did he despair of his own and the public fortune, till, by the confession of his enemies, he had exhausted every resource both of valor and policy. 16 This memorable war, with a very short suspension of hostilities, lasted five years; and as the emperor could exert, without control, the whole force of the state, it was terminated by an absolute submission of the barbarians.17 The new province of Dacia, which formed a second exception to the precept of Augustus, was about thirteen hundred miles in circumference. Its natural boundaries were the Niester, the Teyss or Tibiscus, the Lower Danube, and the Euxine Sea. The vestiges of a military road may still be traced from the banks of the Danube to the neighborhood of Bender, a place famous in modern history, and the actual frontier of the Turkish and Russian empires. 18
Trajan was ambitious of fame; and as long as mankind shall continue to bestow more liberal applause on their destroyers than on their benefactors, the thirst of military glory will ever be the vice of the most exalted characters. The praises of Alexander, transmitted by a succession of poets and historians, had kindled a dangerous emulation in the mind of Trajan. Like him, the Roman emperor undertook an expedition against the nations of the East; but he lamented with a sigh, that his advanced age scarcely left him any hopes of equalling the renown of the son of Philip. 19 Yet the success of Trajan, however transient, was rapid and specious. The degenerate Parthians, broken by intestine discord, fled before his arms. He descended the River Tigris in triumph, from the mountains of Armenia to the Persian Gulf. He enjoyed the honor of being the first, as he was the last, of the Roman generals, who ever navigated that remote sea. His fleets ravaged the coast of Arabia; and Trajan vainly flattered himself that he was approaching towards the confines of India. 20 Every day the astonished senate received the intelligence of new names and new nations, that acknowledged his sway. They were informed that the kings of Bosphorus, Colchos, Iberia, Albania, Osrhoene, and even the Parthian monarch himself, had accepted their diadems from the hands of the emperor; that the independent tribes of the Median and Carduchian hills had implored his protection; and that the rich countries of Armenia, Mesopotamia,