Before a blow was struck this simple lodgment of Demosthenes brought about two great results. The Spartan fleet hastened back to the spot, slipping past the Athenian fleet; and the Spartan army, which had made the annual invasion of Attica, came hastily back to Sparta after only fifteen days of occupation. The fleet occupied the bay, and the land army butted its head in vain against the walls on that side. Then came the attempt which Demosthenes had expected. They tried to land in front of his sea-wall. But as the handful of men in possession held their ground not a Spartan reached the shore, though the gallant Brasidas, who here appears as the simple commander of a trireme, tried it with a daring that nearly cost him his life. For nearly two days this attack continued. It failed as signally as the land attack. The Spartans were at their wits' ends. They had sent to Asine, a day's journey distant, for big timbers to make battering-rams and break down the walls toward the mainland. They also landed a force on the island, Sphacteria, to overawe by their proximity the Athenians across the narrow channel, and to prevent any future lodgment of the Athenians on Sphacteria also. When the Spartan fleet had first appeared Demosthenes had sent two of his five triremes to advise the Athenian Admirals that the plot was thickening; and the Athenian fleet, strengthened to fifty sail, appeared off the entrances of the bay; but seeing both entrances defended by the Spartan fleet and the shore crowded with Spartan soldiers, it put about, and, going back to an island a few miles to the north, passed the night there. This was probably a ruse to throw the Spartans off their guard; for the next day the Athenians reappeared, and with no hesitation drove in at both entrances upon the Spartans, who were evidently not thoroughly prepared. After a long and fierce struggle the victory of the Athenians was decisive. They erected a trophy, gave up the Spartan dead, took possession of the wrecks and many of the sound vessels of the enemy, and sailed at will around the bay and the entrances. The main army of the Spartans lay close at hand; but all their hope of getting materials for battering down Demosthenes's landward walls, or of starving out his little band, was cut off. The whole situation was changed at a single blow. The centre of interest shifts to the island, Sphacteria, where the Spartans were now imprisoned. The Athenians thought them sure game, and patrolled the island to cut off escape. The situation was so serious that the highest magistrates of Sparta appeared on the scene, and, after surveying the situation, decided that the only thing to do was to propose a truce. And a truce was immediately agreed upon, all the Spartan ships being given over to the Athenians as a pledge until Spartan envoys could be taken to Athens on an Athenian trireme and secure a permanent treaty of peace.