The Dyarchy. The division of the provinces between Augustus and the Senate in 27 B. C. had the effect of creating an administrative dyarchy, or joint rule of two independent authorities, for the empire. However, the original allotment of the provinces underwent some modification subsequent to 27 B. C. In 23 B. C., Augustus transferred to the Senate Narbonese Gaul where the rapid progress of colonization had made it “more a part of Italy than a province.” In exchange he took over Illyricum, where the progress of the Roman arms had been interrupted by the outbreak of the war with Antony and where the Romans were confronted by warlike and restless peoples of the hinterland. Somewhat later Cilicia also became an imperial province and in 6 A. D. Sardinia was placed under an imperial procurator because of disturbances on the island. Southern Greece, previously dependent upon the province of Macedon, was placed under the government of the Senate as the province of Achaea. New administrative districts organized by Augustus out of territories conquered by his generals remained under his control.
Survey and census of the empire. The main expense of the military and civil establishment of the empire was defrayed by the revenues from the provinces. As a basis for an accurate estimate of their resources for purposes of taxation and recruitment Augustus caused a comprehensive census of the population and an evaluation of property to be taken in each newly organized district, and provided for a systematic revision of the census in all the imperial provinces. In addition a general chart of the empire was compiled on the basis of an extended survey conducted under the direction of Agrippa.
The foreign policy of Augustus. As we have seen, Augustus since he was commander-in-chief of the Roman armies and in charge of the administration of the most important border provinces, was entrusted by the senate with the direction of the foreign relations of the [pg 217]state. Here his aims conformed to the general conservatism of his policies and were directed towards securing a defensible frontier for the empire which should protect the peace that he had established within its borders. His military operations were conducted with due regard to the man power and the financial resources of the state. To secure the defensible frontier at which he aimed it was necessary for Augustus to incorporate in the empire a number of border peoples whose independence was a menace to the peace of the provinces and to establish some client kingdoms as buffer states between Roman territory and otherwise dangerous neighbors.
The settlement in Spain. The northwestern corner of the Spanish peninsula was still occupied by independent peoples, the Cantabri, Astures and the Callaeci, who harassed with their forays the pacified inhabitants of the Roman provinces. To secure peace in this quarter Augustus determined upon the complete subjugation of these peoples. From 27 to 24 B. C. he was present in Spain and between these years his lieutenants Antistius, Carisius and Agrippa conducted campaigns against them in their mountain fastness, and, overcoming their desperate resistance, settled them in the valleys and secured their territory by founding colonies of veterans. A subsequent revolt in 20–19 was crushed by Marcus Agrippa.
The pacification of the Alps, 25–8 B. C. A similar problem was presented by the Alpine peoples, who not only made devastating raids into northern Italy but also in the west occupied the passes which offered the most direct routes between Italy and Transalpine Gaul. In 26 B. C. occurred a revolt of the Salassi, in the neighborhood of the Little St. Bernard, who had been subdued eight years before. In the following year they were completely subjugated, and those who escaped slaughter were sold into slavery. In 16 B. C. the district of Noricum, i. e., modern Tyrol and Salzburg, was occupied by Publius Silius Nerva, in consequence of a raid of the Noricans into the Istrian peninsula. In 15 B. C., the step-son of Augustus, Nero Claudius Drusus, crossed the Brenner Pass and forced his way over the Vorarlberg range to Lake Constance, subduing the Raeti on his way. On the shores of Lake Constance he met his elder brother, Tiberius Claudius Nero, who had marched eastwards from Gaul. Together they defeated and subjugated the Vindelici. On the north the Danube was now the Roman frontier. A number of isolated campaigns completed the subjugation of the remaining Alpine peoples by 8 [pg 218]B. C. Raetia and Noricum were organized as procuratorial provinces, while the smaller Alpine districts were placed under imperial prefects.
Gaul and Germany. Caesar had left the land of Gallia Comata crushed but still unsettled and not fully incorporated in the empire. It fell to the lot of Augustus to complete its organization, which was accomplished between 27 and 13 B. C. Subsequent to the transfer of the Narbonese province to the Senate Gallia comata was divided into three districts; Aquitania, Lugdunensis and Belgica, which, however, during the lifetime of Augustus, formed an administrative unity, under one governor with subordinate legati in each district. The colony of Lugdunum was the seat of the administration, as well as of the imperial cult. No attempt was made to latinize the three Gauls by the founding of Roman colonies; but they remained divided into sixty-four separate peoples, called civitates, with a tribal organization under the control of a native nobility. As early as 27 B. C. Augustus took a census in Gaul, and on this basis fixed its tax obligations. The rich lands of Gaul were as important a source of imperial revenue as its vigorous population was of recruits for the Roman auxiliary forces.
But the Gauls were restive under their new burdens and were in addition liable to be stirred up by the Germanic tribes who came from across the Rhine. An invading horde of Sugambri in 16 B. C. defeated a Roman army and, upon a renewed inroad by the same people in 12 B. C., Augustus determined to cross the Rhine and secure the frontier of Gaul by the subjugation of the Germans to the north. The Germans, like the Gauls at the time of the Roman conquest, were divided into a number of independent tribes usually at enmity with one another and hence incapable of forming a lasting combination against a common foe. Individually they were powerful and courageous, but their military efficiency was impaired by their lack of unity and discipline.
Drusus, conqueror of the Raeti, was appointed to command the Roman army of invasion. He first secured the Rhine frontier by the construction of a line of fortresses stretching from Vindonissa (near Basle) to Castra Vetera (near Xanten), the latter of which, with Mogontiacum (Mainz) were his chief bases. Then, crossing the river, in four campaigns (12–9 B. C.) he overran and subjugated the territory between the Rhine and the Elbe. His operations were greatly [pg 219]aided by his fleet, for which he constructed a canal from the Rhine to the Zuider Zee, and which facilitated the conquest of the coast peoples, among them the Batavi, who became firm Roman allies. On the return march from the Elbe in 9 B. C., Drusus was fatally injured by a fall from his horse. His brother Tiberius succeeded him in command and strengthened the Roman hold on the transrhenene conquests. Drusus was buried in Rome, whither Tiberius escorted his corpse on foot, and was honored with the name Germanicus.
Illyricum and Thrace. To the east of the Adriatic the Roman provinces of Illyricum and Macedonia were subject to constant incursions of the Pannonians, Getae (or Dacians) and Bastarnae, peoples settled in the middle and lower Danube valley. Marcus Licinius Crassus, Governor of Macedonia, in 30 and 29 B. C. defeated the Getae and Bastarnae, crossed the Balkans, carried the Roman arms to the Danube and subdued the Moesi to the south of that river. However, it required a considerable time before the various Thracian tribes were finally subdued and a client kingdom under the Thracian prince Cotys was interposed between Macedonia and the lower Danube. Meantime, the Pannonians had been conquered in a number of hard fought campaigns which were brought to a successful conclusion by Tiberius (12–9 B. C.) who made the Drave the Roman boundary. The contemporaneous conquest of Pannonia and of Germany between the Rhine and the Elbe was one of the greatest feats of Roman arms and reveals the army of the empire at the height of its discipline and organization. In 13 B. C., during a lull in these frontier struggles, the Senate voted the erection of an altar to the peace of Augustus (the ara pacis Augustae), in grateful recognition of his maintenance of peace within the empire.
The revolt of Illyricum and Germany. For several years following the death of Drusus no further conquests were attempted until 4 A. D., when Tiberius was again appointed to command the army of the Rhine. After assuring himself of the allegiance of the Germans by a demonstration as far as the Elbe and by the establishment of fortified posts, he prepared to complete the northern boundary by the conquest of the kingdom of the Marcomanni, in modern Bohemia, between the Elbe and the Danube. In 6 A. D. Tiberius was on the point of advancing northward from the Danube, in coöperation with Gaius Saturninus, who was to move eastwards from the Rhine, when a revolt broke out in Illyricum which forced the abandonment of the [pg 220]undertaking and the conclusion of peace with Marbod, the king of the Marcomanni. The revolt, in which both Pannonians and Dalmatians joined, was caused by the severity of the Roman exactions, especially the levies for the army. For a moment Italy trembled in fear of an invasion; in the raising of new legions even freedmen were called into service. But the arrival of reinforcements from other provinces enabled Tiberius after three years of ruthless warfare to utterly crush the desperate resistance of the rebels (9 A. D.). The organization of Pannonia as a separate province followed the reëstablishment of peace.