History of the Peloponnesian War

The same winter the Athenians resolved to sail again to Sicily, with a greater armament than that under Laches and Eurymedon, and, if possible, to conquer the island; most of them being ignorant of its size and of the number of its inhabitants, Hellenic and barbarian, and of the fact that they were undertaking a war not much inferior to that against the Peloponnesians.

For the voyage round Sicily in a merchantman is not far short of eight days; and yet, large as the island is, there are only two miles of sea to prevent its being mainland.