chronology The 5th millennium has become a startpoint for calendars and chronologies. The year 4750 BC is the retrospective startpoint for the Assyrian calendar, marking the traditional date for the foundation of Assur, some 2,000 years before it actually happened. Another traditional date is 19 July 4241 BC, marking the supposed beginning of the Egyptian calendar, as calculated retrospectively by Eduard Meyer. The more likely startpoint is 19 July 2781 BC, one Sothic cycle later. It has generally been believed that the calendar was based on a heliacal (dawn) rising of Sirius but that view is now being questioned. According to the Ussher chronology, the creation of Earth happened on 22/23 October 4004 BC. This chronology was the work of James Ussher, whose basis was the dates in the Old Testament of the Bible. He estimated that the universe was created by God at either 18:00 on the 22nd (Jewish calendar) or 09:00 on the 23rd (Ussher-Lightfoot-Chronology). Yet another calendar starting date in the 5th millennium is Monday, 1 January 4713 BC, the beginning of the current Julian Period, first described by Joseph Justus Scaliger in the sixteenth century. This Julian Period lasts 7,980 years until the year 3268 (current era) in the next millennium. It is a useful device for date conversions between different calendars. The date of origin has the integer value of zero in the Julian Day Count: i.e., in the Julian Calendar; the equivalent date in the Gregorian Calendar is 24 November 4714 BC. See also Northgrippian References -95