period from which, judged by the wonderful remains of Mycenae, Tiryns, Cnossus and other cities, civilisation in Greek lands appears to date, it seems reasonable to suppose that the octennial cycle, based as it was on very simple observations, for which nothing but good eyes and almost no astronomical knowledge was necessary,(287) may have been handed down among the inhabitants of these countries from ages that preceded by many centuries, possibly by thousands of years, the great period of Greek literature and art. The supposition is confirmed by the traces which the octennial cycle has left of itself in certain ancient Greek customs and superstitions, particularly by the evidence which points to the conclusion that at two of the oldest seats of monarchy in Greece, namely Cnossus and Sparta, the king’s tenure of office was formerly limited to eight years.(288) (M58) We are informed, and may readily believe, that the motive which led the Greeks to adopt the eight years’ cycle was religious rather than practical or scientific: their aim was not so much to ensure the punctual despatch of business or to solve an abstract problem in astronomy, as to ascertain the exact days on which they ought to sacrifice to the gods. For the Greeks regularly employed lunar months in their reckonings,(289) and accordingly if they had dated their religious festivals simply by the number of the month and the day of the month, the excess of eleven and a quarter days of the solar over the lunar year would have had the effect of causing the festivals gradually to revolve throughout the whole circle of the seasons, so that in time ceremonies which properly belonged to winter would come to be held in summer, and on the contrary ceremonies which were only appropriate to summer would come to be held in winter. To avoid this anomaly, and to ensure that festivals dated by lunar months should fall at fixed or nearly fixed points in the solar year, the Greeks adopted the octennial cycle by the simple expedient of intercalating three lunar months in every period of eight years. In doing so they acted, as one of their writers justly pointed out, on a principle precisely the reverse of that followed by the ancient Egyptians, who deliberately regulated their religious festivals by a purely lunar calendar for the purpose of allowing them gradually to revolve throughout the whole circle of the seasons.(290)