Comparison of the Resources of Sparta and of Athens.—The resources of Hellas were, at the outbreak of the war, very evenly divided between the two parties. With Sparta were all the states of the Peloponnesus, save Argos and Achaia, while beyond the Isthmus the Bœotian League, headed by Thebes, and other states were her allies. Together, these states could raise a land force of sixty thousand men, besides a considerable naval armament, Corinth being especially strong in ships.
Athens commanded all the resources of the subject cities—about three hundred in number, with twice as many smaller towns—of her great maritime empire. Her independent allies were Chios, Lesbos, Corcyra, and other states. Of course the chief strength of Athens lay in her splendid navy.
The Beginning: Attack upon Platæa by the Thebans.—The first act in the long and terrible drama was enacted at night, within the walls of Platæa. This city, though in Bœotia, was under the protection of Athens, and would have nothing to do with the Bœotian League.
Anxious to get possession of this place before the actual outbreak of the war which they saw to be inevitable, the Thebans planned its surprise and capture. Three hundred Thebans gained access to the unguarded city in the dead of night, and marching to the public square, summoned the Platæans to exchange the Athenian for a Bœotian alliance.
The Platæans were upon the point of acceding to all the demands made upon them, when, discovering the small number of the enemy, they attacked and overpowered them in the darkness, and took a hundred and eighty of them prisoners. These captives they afterwards murdered, in violation, as the Thebans always maintained, of a sacred promise that their lives should be spared. This wretched affair at Platæa precipitated the war (431 B.C.).
Invasion of Attica: Pestilence at Athens.—A Spartan army was soon overrunning Attica, while an Athenian fleet was ravaging the coasts of the Peloponnesus. Pericles persuaded the country people of Attica to abandon their villas and hamlets and gather
