Читать книгу Universe: The story of the Universe, from earliest times to our continuing discoveries - Peter Grego - Страница 43

A calendar based on the Moon’s cycles was used. Each month began with the first sighting of the narrow crescent Moon at sunset, and 12 lunar months made one year. Since 12 lunar months is 11 days short of a solar year (365 days), the Sumerian calendar was synchronized with the solar year by adding a leap month every three or four years.