The regulation of the Greek calendar has throughout a sacral character. The idea of the selection of lucky or unlucky days prevails not only in superstition but also in the official religious cult. Most of the old festivals fall, according to universal custom, either during or shortly before the time of full moon; the festivals of Apollo form an exception and are all celebrated on the 7th, those of his twin sister Artemis being held on the preceding day, the 6th. The names of months appear in sharp contradistinction to the world-wide method of nomenclature in that they all, in so far as they are explainable, are derived from festivals. Several hundred names are known from the various states of the mother country and the colonies, and among these there is only a single exception to the rule just stated, viz. Ἁλιοτρόπιος, i. e. the solstice month, which belongs to later times, besides a few unexplained names, such as Γεῦστος, Δίνων; numbered months were first created among the leagues of states of the period after Alexander the Great, in order to introduce a means of common understanding such as was necessitated by the multiplicity of the local calendars. These cases are all quite isolated and cannot disturb the rule. The inference that may be drawn in regard to the months from their names and from the ordering of the religious cult is further established by other matters in regard to the cyclical intercalation. The eight-year intercalary cycle cannot be distinguished from the _Ennaeteris_ period (so called according to the Greek inclusive method of reckoning, the eight-year period according to our method of expression) of certain festivals. Such festivals are only known at Delphi, where three of them were held (Charila, Stepterion, Herois). The great Pythian games themselves were originally held every eighth year, and then, after the first holy war (probably in the year 582, from which the Pythiads were counted), every fourth year. Since eight years seemed too long an interval, the period was halved in order to secure a more frequent celebration, and the Isthmian and Nemean games were even held every second year, i. e. the period was divided into four. The Olympiad reckoning will go still farther back, if the traditional starting-point, the year 776 B. C., is to be accepted. However the authenticity of the older portion of the list of Olympian victors has been sharply disputed, though the criticism certainly seems to have weakened a little quite recently. But a peculiarity attaches to this festival, viz. that it is celebrated alternately in one of the two consecutive months, Apollonios and Parthenios[1195]. This can only be explained as follows:--The Oktaeteris has 99 months. Originally the Olympic festival was not fixed according to the calendar, but the date was simply arranged by the numbering of the months of the Oktaeteris, in which the first half of the Oktaeteris was given 50 months and the second 49. In the calendarial