Meton, an Athenian mathematician and astronomer of the C5 BCE (mu 801), "is famous for his introduction of the luni-solar calendaric cycle named after him, with 19 solar years and 235 months, of which 110 were "hollow" (containing 29 days) and 125 full (containing 30 days), making a total of 6,940 days. The basis of the cycle...was undoubtedly derived from Babylonian practice" (OCD, below).
The headword phrase is preserved as proverbial (with a similar but longer gloss) in Appendix Proverbiorum 3.83.