"By about 430 BC the Greek astronomer Meton […] discovered that 235 lunar months correspond very closely to 19 solar years (the so-called Metonic cycle). Some fifty years later the astronomers of the Persian kings, who used the Babylonian calendar, heard of his discovery and used it to regulate the intercalations. Since 19 years of 12 months amount to 228 months, the additional 7 months were intercalated in years 3, 6, 8, 11, 14, 17 and 19. As a result the New Year moved within a period of 27 days around the spring equinox.
Chinese astronomers had established the solar year as 365.25 days and the lunation as 29.5 days well before 1300 BC. Their calendar used 12 lunar months of 29 or 30 days with an intercalation of 7 months of 29 or 30 days over a 19 year cycle (the Metonic cycle). The scientific description of this cycle appeared in Chinese texts between 770 and 476 BC and predates its discovery by Meton by at least 100 years."
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timeasmymeasure
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Date: 2005-01-06 12:12 pm (UTC)Chinese astronomers had established the solar year as 365.25 days and the lunation as 29.5 days well before 1300 BC. Their calendar used 12 lunar months of 29 or 30 days with an intercalation of 7 months of 29 or 30 days over a 19 year cycle (the Metonic cycle). The scientific description of this cycle appeared in Chinese texts between 770 and 476 BC and predates its discovery by Meton by at least 100 years."
And there we have it. ;)