History of the Peloponnesian War
Thucydides
Thucydides, Vol. 1-4. Smith, Charles Foster, translator. London and Cambridge, MA: Heinemann and Harvard University Press, 1919-1923.
for differences in men's actions arise from the diversity of their convictions. "Now between us and the Athenians an alliance was first made when you withdrew from the Persian war but they remained to finish the work.
We became allies, however, not to the Athenians for the enslavement of the Hellenes, but to the Hellenes for their emancipation from the Persians. And as long as they maintained their hegemony on terms of equality we heartily followed their lead;