Nor was it long before the reinforcement actually arrived, after that untoward detention which had wellnigh exposed Phormio and his whole fleet to ruin. It confirmed his mastery of the entrance of the gulf and of the coast of Akarnania, where the Peloponnesians had now no naval force at all. To establish more fully the Athenian influence in Akarnania, he undertook during the course of the autumn an expedition, landing at Astakus, and marching into the Akarnanian inland country with four hundred Athenian hoplites and four hundred Messenians. Some of the leading men of Stratus and Koronta, who were attached to the Peloponnesian interest, he caused to be sent into exile, while the chief named Kynês, of Koronta, who seems to have been hitherto in exile, was reëstablished in his native town. The great object was, to besiege and take the powerful town of Œniadæ, near the mouth of the Achelôus; a town at variance with the other Akarnanians, and attached to the Peloponnesians. But the great spread of the waters of the Achelôus rendered this siege impracticable during the winter, and Phormio returned to the station at Naupaktus. From hence he departed to Athens towards the end of the winter, carrying home both his prize-ships and such of his prisoners as were freemen. The latter were exchanged man for man against Athenian prisoners in the hands of Sparta.[355] [355] Thucyd. ii, 102, 103. After abandoning the naval contest at Rhium, and retiring to Corinth, Knêmus and Brasidas were prevailed upon by the Megarians, before the fleet dispersed, to try the bold experiment of a sudden inroad upon Peiræus. Such was the confessed superiority of the Athenians at sea, that, while they guarded amply the coasts of Attica against privateers, they never imagined the possibility of an attack upon their own main harbor. Accordingly, Peiræus was not only unprotected by any chain across the entrance, but destitute even of any regular guard-ships manned and ready. The seamen of the retiring Peloponnesian armament, on reaching Corinth, were immediately disembarked and marched, first across the isthmus, next to Megara,—each man carrying his sitting-cloth,[356] and his oar, together with the loop whereby the oar was fastened to the oar-hole in the side, and thus prevented from slipping. There lay forty triremes in Nisæa, the harbor of Megara, which, though old and out of condition, were sufficient for so short a trip; and the seamen immediately on arriving, launched these and got aboard. But such was the awe entertained of Athens and her power, that when the scheme came really to be executed, the courage of the Peloponnesians failed, though there was nothing to hinder them from actually reaching Peiræus: but it was pretended that the wind was adverse, and they contented themselves with passing across to the station of Budorum, in the opposite Athenian island of Salamis, where they surprised and seized the three guard-ships which habitually blockaded the harbor of