What is Egyptian calendar?
[[File:Senenmut-Grab.JPG|thumb|right|250px|{{Center|Eighteenth [[dynasty]] calendar found on the ceiling of the tomb of [[Senenmut]]}}]] The [[Ancient history|ancient]] [[wikt:civil |civil ]] '''Egyptian calendar''' was a [[calendar]] used by the [[ancient Egypt]]ians. At first it had a [[year]] that was 365 days long. The year was made up of 12 months each having 30 days. At some point during the [[First Dynasty of Egypt|First Dynasty]] five additional days were added (sometime around 3000 BC).<ref>Marshall Clagett, ''Ancient Egyptian Science'', Volume 2 (Philadelphia: American Philosophical Society, 1995), p. 33</ref> Egyptian [[astronomers]] observed that the [[wikt:annual|annual]] [[flood]] of the [[Nile River]] fell very close to the first [[visibility]] of the star [[Sirius]] in the [[wikt:morning|morning]] sky just before [[sunrise]].<ref name=Ortelius>{{cite web |url=http://www.ortelius.de/kalender/egypt_en.php |title=The Egyptian Calendar |publisher=ortelius.de |access-date=25 December 2015 |archive-date=19 December 2015 |archive-url=https://web.archive.org/web/20151219111314/http://www.ortelius.de/kalender/egypt_en.php |url-status=dead }}</ref> This calendar would drift by 1 day every four years. But this drift was not enough to cause any problems.<ref name=Stern133>Sacha Stern, ''Calendars in Antiquity: Empires, States, and Societies'' (Oxford; New York: Oxford University Press, 2012), p. 133</ref> Even if a person lived to be 60 years old the drift between [[Solar calendar|solar]] and civil calendars would only be 15 days.<ref name=Stern133/> In 238 [[BC]] the [[Decree of Canopus]] added a sixth day every four years to correct this.<ref name=Sellers177>Jane Sellers, ''The Death of Gods in Ancient Egypt'' (East Sussex, UK: Gardners Books, 2007), p. 177</ref> But it was largely ignored.<ref name=Sellers177/> In 30 BCE the [[List of Roman emperors|Roman Emperor]] [[Augustus]] [[reform]]ed the Egyptian calendar by adding a leap day to every fourth year.<ref name=Ortelius/> This brought the Egyptian calen