The expedition against Bithynia had already been undertaken in part by land; all the more were the attacks that were directed against European Greece composed of piratical expeditions by land and sea. If Moesia and Thrace were not permanently occupied by the Goths, they yet came and went there as if they were at home, and roved from thence far into Macedonia. Even Achaia expected under Valerian invasion from this side; Thermopylae and the Isthmus were barricaded, and the Athenians set to work to restore their walls that had lain in ruins since the siege by Sulla. The barbarians did not come then, nor by this route. But under Gallienus a fleet of five hundred sail, this time chiefly Heruli, appeared before the port of Byzantium, which, however, had not yet lost its capacity of defence; the ships of the Byzantines successfully repulsed the robbers. These sailed onward, showed themselves on the Asiatic coast before Cyzicus not formerly attacked, and arrived from thence by way of Lemnos and Imbros at Greece proper. Athens, Corinth, Argos, Sparta, were pillaged and destroyed. It was always something that, as in the times of the Persian wars, the citizens of the destroyed Athens, two thousand in number, laid an ambush for the retiring barbarians, and, under the leadership of their equally learned and brave captain, Publius Herennius Dexippus, of the old and noble family of the Kerykes, with support of the Roman fleet, inflicted a notable loss on the pirates. On the return home, which took place in part by the land route, the emperor Gallienus attacked them in Thrace at the river Nestus and put to death a considerable number of their men.[144] [Sidenote: The imperial government of the Gothic period.] In order completely to survey the measure of misfortune, we must take into account that in this empire going to shreds, and above all in the provinces overrun by the enemy, one officer after another grasped at the crown, which hardly any longer existed. It is not worth the trouble to record the names of these ephemeral wearers of the purple; it marks the situation that, after the devastation of Bithynia by the pirates, the emperor Valerian omitted to send thither an extraordinary commandant, because every general was, not without reason, regarded by him as a rival. This co-operated to produce the almost thoroughly passive attitude of the government in presence of this sore emergency. Yet, on the other hand, undoubtedly a good part of this irresponsible passiveness is to be traced to the personality of the rulers: Valerian was weak and aged, Gallienus vehement and dissolute, and neither the one nor the other was equal to the guidance of the vessel of the state in a storm. Marcianus, to whom Gallienus after the invasion of Achaia had committed the command in these regions, operated not without success; but the matter did not gain any real turn for the better so long as Gallienus occupied the throne. [Sidenote: Gothic victories of Claudius.]