History of the Peloponnesian War

But though they had resolved on it, it was impossible to take it in hand immediately, as they were unprepared; but it was determined that suitable means should be provided by the several states, and that there should be no delay. A year, however, did not pass while they were settling all that was necessary, but less, before they invaded Attica, and openly proceeded to the war.

During this time they were sending ambassadors to the Athenians with complaints, in order that they might have as good a pretext as possible for the war, in case they should not listen to them.