This article examines the disconnect between, on the one hand, the insistence on the part of multiple characters in Thucydides’ first book on the need for the Peloponnesians to invest in naval power to defeat Athens, and, on the other, the failure to act on this in the narrative of books 2–7. It then analyses the numismatic evidence for the way in which Sparta does then act upon this advice in the course of the Ionian War, and suggests that Thucydides’ (...) view that this was done primarily with Persian support may be missing a (brief) Spartan attempt to create a fiscally self-supporting empire. (shrink)