For seven years longer Alexander continued his nefarious practices, henceforth turning his attention to piracy and the plunder of the islands and coast towns. In the general confusion his audacity went so far that he is said to have once surprised the Piræus in an unguarded hour and carried off a rich booty. Finally, at the instigation of his wife, Thebe, who on a former occasion had excited the imprisoned Pelopidas against her cruel husband, he was murdered by her brothers. [Sidenote: [366-362 B.C.]] The piratical expeditions with which Alexander afflicted the northern waters, were probably carried out with the knowledge and connivance of Thebes, for the purpose of annoying the Athenians. The latter, especially since their alliance with Sparta, had made the most eager efforts to re-establish their influence over the maritime states, though their means and forces were small and the mercenaries and peltasts who manned their ships little fitted to supply the place of the old citizen army. Iphicrates cruised in the northern waters for the space of three years, attempted to bring back the Greek cities in Thrace and Macedon to their old relation with Athens and made repeated attacks on Amphipolis, but without being able to win back this ancient colony; Timotheus brought Samos into subjection, and, with the help of the revolted Persian governor Ariobarzanes, acquired Sestos and Crithote on the Thracian Chersonesus, whereby the relations with Byzantium were restored, and also won a firm footing in Chalcidice and the Gulf of Thermæ by taking Potidæa and Torone, as well as Methone and Pella. These successes of Athens, though small in comparison with her former dominion over the sea and coasts, and insecure as they were in face of the impossibility of permanently providing the hired troops with pay and maintenance, nevertheless awakened the jealousy of Thebes. The keen eye of Epaminondas did not fail to perceive that his native city could only attain to the hegemony of Greece if the dominion of the sea were snatched from the Athenians, and being as bold and enterprising as he was sagacious, he endeavoured to persuade his countrymen to build a fleet. Thebes must become a sea power, in order, as he declared before the people, “to place the Propylæa of the Athenian Acropolis under the superintendence of the Cadmea”; not that he wished to accustom the powerful national forces to the seductive life on the sea and thus weaken the heavy-armed militia; the old manner of warfare, which rested on custom, education, and tradition, was to continue to prevail; but for the foundation of a secure ascendency in Hellas a fleet was indispensable. And so influential was the voice of this great general, that in spite of the remonstrance of the popular orator Meneclidas, the Theban people immediately resolved on the building and equipment of a hundred triremes and the establishment of shipyards of their own.