Of these two conquests one alone was permanent, that of Dacia. The provinces conquered from the Parthians revolted after the departure of the Roman army. The emperor Hadrian retained Dacia, but returned their provinces to the Parthians, and the Roman empire again made the Euphrates its eastern frontier. To escape further warfare with the highlanders of Scotland, Hadrian built a wall in the north of England (the Wall of Hadrian) extending across the whole island. There was no need of other wars save against the revolting Jews; these people were overthrown and expelled from Jerusalem, the name of which was changed to obliterate the memory of the old Jewish kingdom.
Marcus Aurelius, the last of the Antonines, had to resist the invasion of several barbarous peoples of Germany who had crossed the Danube on the ice and had penetrated even to Aquileia, in the north of Italy. In order to enroll a sufficient army he had to enlist slaves and barbarians (172). The Germans retreated, but while Marcus was occupied with a general uprising in Syria, they renewed their attacks on the empire, and the emperor died on the banks of the Danube (180). This was the end of conquest.
IMPERIAL ADMINISTRATION
Extent of the Empire in the Second Century.—The Roman emperors were but little bent on conquest. But to occupy their army and to secure frontiers which might be easily defended, they continued to conquer barbarian peoples for more than a century. When the course of conquest was finally arrested after Trajan, the empire extended over all the south of Europe, all the north of Africa and the west of Asia; it was limited only by natural frontiers—the ocean to the west; the mountains of Scotland, the Rhine, the Danube, and the Caucasus to the north; the deserts of the Euphrates and of Arabia to the east; the cataracts of the Nile and the great desert to the south. The empire, therefore, embraced the countries which now constitute England, Spain, Italy, France, Belgium, Switzerland, Bavaria, Austria, Hungary, European Turkey, Morocco, Algiers, Tunis, Egypt, Syria, Palestine, and Asiatic Turkey. It was more than double the extent of the empire of Alexander.
This immense territory was subdivided into forty-eight provinces,[147] unequal in size, but the majority of them very large. Thus Gaul from the Pyrenees to the Rhine formed but seven provinces.
The Permanent Army.—In the provinces of the interior there was no Roman army, for the peoples of the empire had no desire to revolt. It was on the frontier that the empire had its enemies, foreigners always ready to invade: behind the Rhine and the Danube the barbarian Germans; behind the sands of Africa the nomads of the desert; behind the Euphrates the Persian army. On this frontier which was constantly threatened it was necessary to have soldiers always in readiness. Augustus had understood this, and so created a permanent army. The soldiers of the empire were no longer proprietors transferred from their fields to serve during a few campaigns, but poor men who made war a profession. They enlisted for sixteen or twenty years and often reënlisted. There were, then, thirty legions of citizens—that is, 180,000 legionaries, and, according to Roman usage, a slightly larger number of auxiliaries—in all about 400,000 men. This number was small for so large a territory.
Each frontier province had its little army, garrisoned in a permanent camp similar to a fortress. Merchants came to establish themselves in the vicinity, and the camp was transformed into a city; but still the soldiers, encamped in the face of the enemy, preserved their valor and their discipline. There were for three centuries severe wars, especially on the banks of the Rhine and of the Danube, where Romans fought fierce barbarians in a swampy country, uncultivated, covered with forests and bogs. The imperial army exhibited, perhaps, as much bravery and energy in these obscure wars as the ancient Romans in the conquest of the world.
Deputies and Agents of the Emperor.—All the provinces belonged to the emperor[148] as the representative of the Roman people. He is there the general of all the soldiers, master of all persons, and proprietor of all lands.[149] But as the emperor could not be everywhere at once, he sent deputies appointed by himself. To each province went a lieutenant (called a deputy of Augustus with the function of prætor); this official governed the country, commanded the army, and went on circuit through his province to judge important cases, for he, like the emperor, had the right of life and death.
The emperor sent also a financial agent to levy the taxes and return the money to the imperial chest. This official was called the "procurator of Augustus." These two men represented the emperor, governing his subjects, commanding his soldiers, and exploiting his domain. The emperor always chose them among the two nobilities of Rome, the prætors from the senators, the procurators from the knights. For them, as for the magistrates of old Rome, there was a succession of offices: they passed from one province to another, from one end of the empire to the other,[150] from Syria to Spain, from Britain to Africa. In the epitaphs of officials of this time we always find carefully inscribed all the posts which they have occupied; inscriptions on their tombs are sufficient to construct their biographies.
Municipal life.—Under these omnipotent representatives of the emperor the smaller subject peoples continued to administer their own government. The emperor had the right of interfering in their local affairs, but ordinarily he did not exercise this right. He only demanded of them that they keep the peace, pay their taxes regularly, and appear before the tribunal of the governor. There were in every province several of these little subordinate governments; they were called, just as at other times the Roman state was called, "cities," and sometimes municipalities. A city in the empire was copied after the Roman city: it also had its assembly of the people, its magistrates elected for a year and grouped into colleges of two members, its senate called a curia, formed of the great proprietors, people rich and of old family. There, as at Rome, the assembly of the people was hardly more than a form; it is the senate—that is to say, the nobility, that governs.