Oktaeteris, on the other hand, there is an intercalation once in the first half and twice in the second, i. e. the first four years have 49 months and the next four 50; hence it follows that when the old custom was to be preserved in regard to the date, the month of the festival necessarily varied in the given manner. When the chronological arrangement of the Olympic games was introduced, the Oktaeteris calendar therefore was not known, but only the Oktaeteris period. The introduction of the calendar was effected in the form of the establishment of _fasti_ for festivals and religious cult, in which the periodically recurring notable events of the cult, viz. sacrifices and festivals, were noted down in calendrical succession and in some cases also described. Fragments of these _fasti_ from later times have in several cases come down to us, and similar _fasti_ formed part of the legislation of Solon. Solon in the year 594 arranged the sacral _fasti_ of Athens, and with them the calendar. That he was the first to introduce the calendar cannot be stated; there is no evidence to shew that the specific peculiarities of the Athenian calendar were introduced by him. The evidence is however valuable as a _terminus ante quem_. Plato in his _Laws_ prescribes that the legislation shall arrange the festivals according to the decrees of Delphi. Here, as elsewhere in the _Laws_, he returns to the general Greek custom. The _fasti_ were therefore arranged under the superintendence of Delphi, and Solon also had certainly done the same, for he stood in other respects in close connexion with Delphi. In addition to which Geminos mentions “the commandment of the laws and the oracular decrees, to sacrifice in three ways, i. e. monthly, daily, yearly”. At a later period also, those who superintended the calendar were men learned in sacral matters. Thus the seer Lampon, at the time of the Peloponnesian War, brought forward a proposal for the intercalation of a month; he was an _exegetes_ and perhaps even πυθόχρηστος.