The lunar year of twelve moons being eleven days shorter than the solar year, to preserve a correspondence between them it was necessary once in about three years, to intercallate a month to fill up the deficiency. Meton, a celebrated astronomer, b. c. 430, discovered that an intercallation of seven lunations in nineteen lunar years, made them correspond very nearly to nineteen solar years, varying a day only once in three hundred and twelve years. His discovery was inscribed by the Greeks on a marble pillar, in letters of gold. Hence the current years of this cycle are called the “Golden Number.” ASC 9.2