This paper focuses on two problems connected with our sources for Athenian politics between 510/09 and 488/7 B.C.: In the Athenaion Politeia attributed to Aristotle, ostracism is included in the laws of Cleisthenes. But later the author of the Ath. dates the first ostracism to the year 488/7. Depending on the date of Cleisthenes' laws, this leaves a gap of thirteen to twenty years between the institution of ostracism and its first use. Yet the very nature of the law suggests (...) that it was passed for immediate use. Cleisthenes' rival, Isagoras, is described in Ath. 20.1 as φίλος τῶν τυράννων. This label conflicts with two details in the political struggle. It involves Cleomenes, who had recently expelled the tyrants from Athens, in an astounding volte-face in supporting one who is known as φίλος τῶν τνράννων. Secondly, Isagoras had had the opportunity of imposing by force the kind of government he wanted—but it was an oligarchy, not a tyranny. How did the inappropriate label originate?The reaction of most scholars to the first problem has been to reject the ascription of ostracism to Cleisthenes in Ath. 22.1 and 22.4 and date the institution of ostracism to shortly before the first recorded ostracism. (shrink)