Golden Number. The discovery of the Greek astronomer Meton in 432 B.C. that a period of 19 years brought the sun, the earth, and the moon approximately into the same relative positions, furnished a convenient means of marking time. The number of a year in the Metonic Cycle became known as the Golden Number from the circumstance that in the Roman and Alexandrian calendars these numbers were inscribed in gold. When the Gregorian calendar was adopted, the 1st of January of the year 1 B.C., on which day there was a new moon, became the starting-point from which the Metonic Cycles were reckoned. The golden number of a year may therefore be ascertained by adding 1 and dividing by 19; the quotient gives the number of previous cycles, and the remainder the number of the year in the present cycle.