Mathematics Throughout History

Math and Calendars in History

When were the first calendars invented?

Although the first crude types of calendars may have appeared some 30,000 years ago—based on the movements of the Moon and found as marks on bones—the Egyptians are given credit for having the first true calendars. Scientists believe that around 4500 B.C.E., the Egyptians needed such a tool to keep track of the Nile River’s flooding. From about 4236 B.C.E., the beginning of the year was chosen as the heliacal rising (when a star is finally seen after being blocked by the Sun’s light) of the star Sirius, the brightest star in the sky located in the constellation of Canis Major. This occurred (and still occurs) in July, with the Nile flooding shortly after, which made it a perfect starting point for the Egyptian calendar. The Egyptians divided the calendar into 365 days, but it was not the only calendar they used. There was also one used for planting and growing crops that was dependent on the lunar month.


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