More serious and continuous watch was needed farther down on the lower Danube. There, beyond the mighty stream, which was now the boundary of the empire, were settled in the plains of Wallachia and the modern Transylvania the Daci; in the eastern flat country, in Moldavia, Bessarabia, and onward, in the first instance, the Germanic Bastarnae, and then Sarmatian tribes, such as the Roxolani, a people of horsemen like the Jazyges, at first between the Dnieper and Don (iii. 295) {iii. 281.}, then advancing along the sea-shore. In the first years of Tiberius the vassal prince of Thrace strengthened his troops to ward off the Bastarnae and Scythians; in the latter years of Tiberius it was urged among other proofs of his government more and more neglecting everything, that he suffered the inroads of the Dacians and the Sarmatae to pass unpunished. How matters went on in the last years of Nero on either side of the mouths of the Danube is approximately shown by the accidentally preserved report of the governor of Moesia at that time, Tiberius Plautius Silvanus Aelianus. The latter "brought upwards of 100,000 men dwelling beyond the Danube, with their wives and children, and their princes or kings over the river, so that they became liable to pay tribute. He suppressed a movement of the Sarmatae before it came to an outbreak, although he had given away a great part of his troops for the carrying on of war in Armenia (to Corbulo). A number of kings hitherto unknown or at feud with the Romans he brought over to the Roman bank, and compelled them to prostrate themselves before the Roman standards. To the kings of the Bastarnae and Roxolani he sent back their sons, who had been made captive or recovered from the enemy, to those of the Dacians their captive brothers,[125] and took hostages from several of them. Thereby the state of peace for the province was confirmed as well as further extended. He induced also the king of the Scythians to desist from the siege of the town Chersonesus (Sebastopol) beyond the Borysthenes. He was the first who, by great consignments of corn from this province, made bread cheaper in Rome." We perceive here clearly as well the agitated vortex of peoples on the left bank of the Danube under the Julio-Claudian dynasty, as also the strong arm of the imperial power, which even beyond the stream sought to protect the Greek towns on the Dnieper and in the Crimea, and was able also in some measure to do so, as will be further set forth when we describe the state of Greek affairs. [Sidenote: Inadequacy of Roman forces.]