Certain passages in Thucydides have caused a good deal of scholarly embarrassment. To the literal-minded they are distracting excrescences that should not be there. The passages in question are the account of Harmodius and Aristogeiton (6.53.3–59), the discussion of the origins of the Cylonian revolt and the subsequent Alcmaeonid curse (1.126.2–12), the end of Pausanias (1.128–135.1) and the fate of Themistocles (1.135.2–138). There is no shortage of critics who have used the terms “digression” or “excursus” to describe these passages. It will be argued here and in Chapter 11 that they are, instead, central to Thucydides' narrative.

In the case of the Harmodius and Aristogeiton passage that comes in the middle of Thucydides' account of Alcibiades' summons from Catana, his escape from his escort, and his exile in the Peloponnese (6.53.1–2, 60–61), “scholars have been puzzled by Thucydides' inclusion of a lengthy and somewhat loosely connected digression in an otherwise tightly-knit narrative that shuns extraneous material”, and the chapters in question have either been held to “provide an historical model for a crucial issue” on which the Peloponnesian War would turn, or else to have nothing whatever to do with the events of 415. On the latter view, Thucydides simply succumbed “to the temptation before which all historians and commentators are by their very nature weak, the temptation to correct historical error wherever they find it, regardless of its relevance to their immediate purpose”.