Islamic Calendar - The Hijri calendar or Muslim Calendar has 12 months in the year which consist of 354 or 355 days. The months and days of Hijri calendar begins and ends according to appearance and different phases of moon. Islamic Calendar starts from the month of Muharram and ends on Zul-Hijja. Prophet Muhammad (P.B.U.H) and the Second Caliph, Umar ibn Al-Khattab first introduced it in 638 A.D. Islamic Calendar is mostly used in Muslim countries for the Islamic holydays and several religious events. Download Islamic Calendar 2011 at Hamariweb.com to find Muslim dates and events around the globe.