EGIRA. - From the Arabic hijrah, “emigration.” It designates Maometto (v.) from Mecca to Medina; with it the Muslim era begins.
The precise day of the prophet’s emigration, according to the most widespread opinion, would have been 8 rahb' al-sassal (that is, 20 Sept. 622); according to other Muslim sources, the day would have been the 2nd or the 12th of the same month. It was the caliph 'Omar, the first organizer of the new Muslim State, who decided to introduce the new era for dating, because, it seems, he was reproached for sending letters without a date. The use of this dating was introduced, according to the most widespread tradition, in the 17th year of the era.
Previously, the Arabs gave each year a special name (e.g., “year of the earthquake,” etc.), or counted the years from some extraordinary or important event. It should be noted that the new era (based on a purely lunar calendar) does not in fact begin with the Egira properly so called, that is, with 8 rubi' al-atamal of 622, but rather with 1 mubarram (the first month of the Muslim year) of that same year. Alessandro Bassani