The ancient Babylonian calendar and the modern Hebrew (Jewish) calendar add an extra month just before the spring equinox on a regular schedule of years: years 3, 6, 8, 11, 14, 17 and 19 of each 19-year cycle
Taken from "Metonic Cycle" on Wikipedia
If you're following the rabbinocal calendar, you're following Babylon.
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Mark Price
I admit that I do not have a great deal of knowledge of other calendars. But it bothers me that there is no unity on the calendar issue. It is easier to stick to the modern Hebrew calendar because that is the mainstream calendar.
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