The claim that the truest reason was >>most concealedcooked up by the Spartans < (as DE STE CRoIX after D. H. 831-2. Thuc. 10 alleges20), but a more fundamental explanation is to be found in Sparta's fear of Athens (though DE STECROIX objects to a distinction on these lines21). The one place where the truest reason cannot be concealed is book I of Thucydides, since his main theme is that other people have not given this reason the weight which it deserves.