At noster Ennius CCCLXVI. The nations also endeavoured to reduce the addition of the 13th Lunar month to a certain rule And particularly the Greeks first added it every other year, or every fourth year, then Cleostratus & others thrice in eight years & Meton seven times in 19 years, & some used months of 29 & 30 days alternately &c And by the use of such like rules various sorts of artifical years