Ancient Egyptian Calendars

The existence of calendars and the concept of measuring the passage of time in yearly cycles is something we take for granted. It was the Ancient Egyptians who we have to thank for our understanding of astronomy. The calendars they created in roughly 4236 B.C.E provided a solid foundation for later civilizations to build off of, evident in the Julian and Gregorian calendars. They experimented with both sidereal and solar calendars that worked concurrently with each other as they served different purposes. The solar calendar followed civil commitments, whilst the lunar calendar had a more traditional role in recognizing religious celebrations and agricultural patterns. The ancient Egyptians were also pivotal in understanding how to successfully

They used the motion of the stars to follow religious practices, because they believed the gods resided in the constellations. In order to pay respect to important powerful figures they erected pyramids with astronomical orientations. Orion, the god of death and afterlife, was present within the constellation of Orios, so they aligned the three pyramids of Giza Plateau with its belt. The horizon also held symbolic importance, as that was where the sun would rise and set.

The sun embodied three different gods depending on its location. The rising sun was Horus, the divine child of both Osiris and Isis, the god of Ra was reflected at noon due its prominence and strength, and the setting sun was Atum and its role was to lift the tombs of the pharos into the sky. The ancient Egyptian’s belief in immortality led them to associate the sun with rebirth and life and the night with death. Thus due to the grave importance of the stars, the Egyptians utilized a sidereal calendar.

The first ancient Egyptian calendar was originally dictated by the lunar phases. They recognized temporal days by the quarters of the moon, and divided night and day into 12 hours successively. The days were dictated by the rising and setting of the sun, which eventuated in the disappearance of the old moon, and so the months began when the waning crescent moon had

H Breasted). This became known as the civil calendar as it was used for administrative purposes. The calendar followed the helical rising of Sirius, otherwise known as the ‘dog star’, which appeared before sunrise and preceded the annual flood. The calendar closely replicated the true solar year, but was 12 minutes short. The year was a 360-day cycle with 5 epagomenal days, which was broken down into 12 months of 30 days each. The extra epagomenal days in the calendar were denoted as ‘unlucky’ for the Ancient Egyptians as it was believed that the goddess of Sehkment was determined to destroy mankind during this period. The civil calendar was later referred to as the ‘wandering calendar’ as its synchronicity with the seasons slowly fell out of line due to its nature of being 1/4th of a day