Sothic cycle
About the Sothic cycle
Because the Egyptian civil year had exactly 365 days, the heliacal rising of Sirius, Sopdet in Egyptian, drifted through it by a day every four years, returning to the civil new year after about 1460 Julian years. The Roman writer Censorinus recorded such a coincidence in 139 CE, and Egyptologists have used the cycle to try to anchor Egyptian chronology.
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