One of the earlier and more brilliant of the Greek tyrannies was that of the Orthagorids at Sicyon. It lasted for a whole century, which established a record for this somewhat unstable form of government. Of the founder and eponym Orthagoras, and of his immediate successors, we know very little, but its most distinguished figure, Cleisthenes, a contemporary of Solon at Athens, played a major role in the First Sacred War and made little Sicyon one of the most important of Greek cities in the first generation of the sixth century. He was also the grandfather of the Cleisthenes who established the Athenian democracy at the end of the century. There is, however, no specific dating in the ancient sources either for Orthagoras at the beginning of the hundred years of the tyranny or the deposition of the last tyrant Aeschines at the end. Various writers give genealogies of the family which are, of course, useful, but only for Cleisthenes and his two brothers Myron II and Isodemus, who preceded him, do we have the lengths of reigns.1 The uncertainties concerning the predecessors and successors of the three brothers make the dating of the Sicyonian tyranny one of the serious chronological problems of the seventh and sixth centuries. Opinions vary by as much as fifty years, some dating the tyranny ca. 656/5 to 556/5 and others ca. 615 to 515-510 B.C. In recent articles D. M. Leahy and N.G.L. Hammond have reopened the controversy.2 They have re-examined Rylands Papyrus 18 and discussed the date of the deposition of Aeschines. Hammond has examined also the various genealogies of the Orthagorid family, and from the papyrus and the genealogies has defended the earlier date of the tyranny. My purpose here is to reconsider the papyrus, and from the combined evidence of papyrus, genealogies, and other references to support the lower dating. First, let us look at the lines of the papyrus which refer to the Spartan deposition of tyrants. Plate 1 is a photograph of the papyrus.3 Column i