Callippic Period

The correction of the Metonʹic cycle by Callippos. In four cycles, or seventy-six years, the Metonic calculation was seven and a-half in excess. Callippos proposed to quadruple the period of Meton, and deduct a day at the end of it: at the expiration of which period Callippos imagined that the new and full moons returned to the same day of the solar year.