Thucydides, History of the Peloponnesian War
Benjamin Jowett, Ed.

29. When he had concluded the affair in the assembly, and the Athenians had passed the necessary¹ vote for his expedition, he made choice of Demosthenes, one of the generals at Pylos, to be his colleague, and proceeded to sail with all speed. [2] He selected Demosthenes because he heard that he was already intending to make an attack upon the island; for the soldiers, who were suffering much from the discomfort of the place, in which they were rather besieged than besiegers², were eager to strike a decisive blow, He had been much encouraged by a fire which had taken place in the island. [3] It had previously been nearly covered with wood and was pathless, having never been inhabited; and he had feared that the nature of the country would give the enemy an advantage. For, however large the force with which he landed, the Lacedaemonians might attack him from some place of ambush and do him much injury. Their mistakes and the character of their forces would be concealed by the wood; whereas all the errors made by his own army would be palpable, and so the enemy, with whom the power of attack would rest, might come upon them suddenly wherever they liked. [4] And if they were compelled to go into the wood and there engage, a smaller force which knew the ground would be more than a match for the larger number who were unacquainted with it. Their own army, however numerous, would be destroyed without knowing it, for they would not be able to see where they needed one another's assistance.