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 Greek astronomer Callippus expanded on the work of Meton, proposing what is now called the Callippic cycle.
[2][3] The foundations of Meton's observatory in Athens are still visible just behind the podium of the Pnyx, the ancient parliament.
So from Meton's observatory the Sun appears to move along a 60° arc between these two points on the horizon every six months.
These topological features are important because the summer solstice was the point in time from which the Athenians measured the start of their calendar years.