Agolden number (sometimes capitalized) is a number assigned to eachyear in sequence which is used to indicate the dates of all thecalendric new moons for each year in a 19-yearMetonic cycle. They are used incomputus (the calculation of the date ofEaster) and also inRunic calendars.
The golden number of anyJulian orGregorian calendar year can be calculated by dividing the year by nineteen, taking the remainder and adding one.[1] (In mathematics this can be expressed as ((year numbermodulo 19) + 1).
For example, 2025 divided by 19 gives 106, remainder 11, which after adding 1 gives the golden number 12.
The golden number, as it was later called, first appears in a calendar composed byAbbo of Fleury around the year 1000. Around 1162 a certain Master William referred to this number as the golden number "because it is more precious than the other numbers."[2] The name refers to the practice of printing golden numbers in gold.[3] The term became widely known and used, in part through the computistic poemMassa Compoti written byAlexander de Villa Dei around 1200.[4]
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