Islam
important turning point in Muhammad's fortunes. The assignment of this year as the year 1
AH (Anno Hegirae) in the Islamic calendar was reportedly made by Caliph Umar. It is a lunar
calendar, with nineteen ordinary years of 354 days and eleven leap years of 355 days in a
thirtyyear cycle. Islamic dates cannot be converted to CE/AD dates simply by adding 622
years: allowance must also be made for the fact that each Hijri century corresponds to only
97 years in the Christian calendar. The year 1428 AH coincides almost completely with 2007
CE.
Islamic holy days fall on fixed dates of the lunar calendar, which means that they occur in
different seasons in different years in the Gregorian calendar. The most important Islamic
festivals are Eid alFitr on the 1st of Shawwal, marking the end of the fasting month
Ramadan, and Eid alAdha on the 10th of Dhu alHijjah, coinciding with the pilgrimage to
Mecca.