Meton of Athens

Meton of Athens was a mathematician, astronomer and engineer who lived in Athens in the 5th century BC. He is best known for the 19-year Metonic Cycle which he introduced into the Athenian luni-solar calendar as a method of calculating dates. It was his observation that a period of 19 solar years (6,940 days) is almost exactly 235 synodic or lunar months, with an error of only 2 hours between 19 years and 235 months. This cycle can be used to predict eclipses, forms the basis of the Greek and Jewish calendars, and is used to determine the date for Easter each year. He worked closely with