In 2015 Muslims in many countries celebrated Prophet Mohammad birthday on January 3 based on modern calendar. Every year this date is shifted in accordance with lunar calendar. Lunar calendar is used in Islam to determine religious holidays’ dates and it is also used as an official calendar in some Muslim countries. Chronology begins from Hijra (July 16, 622 A.D.) – from the day when Prophet Mohammad and the early Muslims left Mecca for Medina. Еще