History of the Peloponnesian War

The Lacedaemonians, as they intended before, and being also instigated to it by the Syracusians and Corinthians, upon advertisement now of the Athenians' new supply for Sicily, prepared likewise to invade Attica, thereby to divert them. And Alcibiades also importunately urged the fortifying of Deceleia, and by no means to war remissly.

But the Lacedaemonians were heartened thereunto principally because they thought the Athenians having in hand a double war, one against them and another against the Sicilians, would be the easier pulled down, and because they conceived the breach of the last peace was in themselves. For in the former war, the injury proceeded from their own side, in that the Thebans had entered Plataea in time of peace; and because also, whereas it was inserted in the former articles that arms should not be carried against such as would stand to trial of judgment, they had refused such trial when the Athenians offered it. And they thought all their misfortunes had deservedly befallen them for that cause, remembering amongst others, the calamity at Pylus.