History of the Peloponnesian War

which the Athenians and Peloponnesians began by breaking the thirty years' truce after the taking of Euboea.

As for the reason why they broke it, I have first narrated their grounds of complaint and their differences, that no one might ever have to inquire from what origin so great a war broke out amongst the Greeks. For the truest reason, though least brought forward in words, I consider to have been, that the Athenians, by becoming great, and causing alarm to the Lacedaemonians, compelled them to proceed to hostilities.

But the following were the grounds of complaints openly alleged on either side, from which they broke the truce, and set to the war.