Augustan age, these insubordinate tribes pressed directly upon Italy. If the emperor subsequently, in the collective report on his imperial administration, declared that violence had not been wrongfully employed by him against any of these small tribes, this must be understood to the effect that cessions of territory and change of abode were demanded of them, and they resisted the demand; only the petty cantonal union formed under king Cottius of Segusio (Susa) submitted without a struggle to the new arrangement. [Sidenote: Subjugation of the Raeti.] The southern slopes and the valleys of the Alps formed the arena of these conflicts. The establishment of the Romans on the north slope of the mountains and in the adjoining country to the northward followed in 739 {15.}. The two step-sons of Augustus reckoned as belonging to the imperial house, Tiberius the subsequent emperor, and his brother Drusus, were thereby introduced into the career of generalship for which they were destined; very secure and very grateful were the laurels put before them in prospect. Drusus penetrated from Italy up the valley of the Adige into the Raetian mountains, and achieved here a first victory; for the farther advance his brother, then governor of Gaul, lent him a helping hand from Helvetia; on the lake of Constance itself the Roman triremes defeated the boats of the Vindelici; on the emperor's day, the 1st August 739 {15.}, in the vicinity of the sources of the Danube, fought the last battle, whereby Raetia and the land of the Vindelici--that is, the Tyrol, East Switzerland, and Bavaria--became thenceforth constituent parts of the Roman empire. The emperor Augustus had gone in person to Gaul to superintend the war and the organisation of the new province. At the point where the Alps abut on the Gulf of Genoa, on the height above Monaco, a monument commanding a wide prospect of the Tyrrhene Sea, and not even yet wholly effaced, was erected some years later by grateful Italy to the emperor Augustus, because under his government all the Alpine tribes from the Upper to the Lower Sea--the inscription enumerates forty-six of them--had been brought under the power of the Roman people. It was no more than the simple truth; and this war was what war ought to be--the guardian and the guarantee of peace. [Sidenote: Organisation of Raetia.]