Meton of Athens

Who is Meton of Athens?

Meton of Athens was a Greek mathematician, astronomer, geometer, and engineer who lived in Athens in the 5th century BC. He is best known for calculations involving the eponymous 19-year Metonic cycle which he introduced in 432 BC into the lunisolar Attic calendar.

The metonic calendar incorporates knowledge that 19 solar years and 235 lunar months are very near equal, thus lunar periods repeat on the same day of the year as 19 years previous. This system was based on calculations made by Meton using his own observations of the summer solstice in 432 BC, and an observation made by Aristarchus 152 years later. Meton's observations were made in collaboration with Euctemon about whom nothing else is known. The Greek astronomer Callippus continued the work of Meton, proposing what is now termed the Callippic cycle. The Callippic cycle is 76 years long, four Metonic cycles. Callippus refined the Metonic cycle, deducting one day every four Metonic after 940 synodic lunar periods to synchronize the lunar calendar with the year.