The precision with which Tiberius was able to time the arrival of the army of Saturninus indicates a greater knowledge of the geography of the districts north of the Alps, and a less savage condition of those regions, than the statements of Cæsar would lead us to imagine possible. We can hardly take literally the statement of Paterculus that Sentius was told to cut through the Hercynian forest; such work may have been necessary on the watershed of the Neckar and the Danube, or, if, as is most probable, the advance was made by a more northerly route, between the Main and the Danube, but when once in the basin of the Danube, the Roman soldiers must have found their way fairly open, and they must further have found sufficient supplies of food. The central uplands of Germany were then as now covered with forests and more thickly covered, but there must have been known tracks along which an army could be led. In the southern basin of the Upper Danube, after the conquest of the Vindelici, a Roman military colony had been founded at Augsburg, indicating that measures were rapidly taken to sweep the rich country north of the Alps into the net of the Empire. Everywhere the traders, whose chief business was slave hunting, pushed in advance of the Roman armies, and Tiberius was thus able to get sufficiently accurate information to launch an army upon the country north of Vienna from the north-west, timed to meet his own advance from the south-east. The conception was a daring one, and the accuracy with which it was carried out would be admirable even today. To render such elaborate strategy successful a commander must not only be able to plan accurately, but he must be able to depend on the obedience of his subordinates and possess their absolute confidence. The rising in Pannonia was of a very serious nature. During the interval of seventeen years since Tiberius had last waged war in that direction the country had become so far Romanized as to have adopted to a large extent the language of its conquerors; garrisons of veterans had been established, and the war began with a general slaughter of these, of resident Roman citizens and of travelling merchants. The province of Macedonia was invaded and devastated. At Rome panic prevailed; Augustus publicly declared that the enemy was within ten days’ march of the city; levies were held, veterans were called back to the colours, and men and women alike were compelled to enfranchise a certain proportion of their slaves according to the amount of their assessed property, that they might be enrolled in the armies. Paterculus was put in command of the reinforcements that were sent to Tiberius from Rome.