Islamic, Christian and Jewish (Hebrew) Calendars As we approach the new years of both the Islamic and Christian (Gregorian) calendars, it would be appropriate to review the basics of the Islamic, Jewish and Christian calendars. Jewish Calendar The Jewish calendar (Hebrew calendar) is based on lunisolar calendar (based on phases of the moon and the solar cycles). The calendar is based on the creation, which according to Jewish religion happened around 3760 BC. This calendar has anywhere between 353 to 385 days. New day in the Jewish calendar starts at sunset. The twelve regular months include: Nisan, Iyar, Sivan, Tammuz, Av, Elul, Tishrei, Marcheshvan, Kislev, Tevet, Shevat, and Adar. Islamic Calendar The Islamic calendar (also known as the Hijri calendar) The calendar is based on the lunar cycle (based on the phases of the moon). It is believed that Caliph Umar (second Capliph after the death of prophet Muhammad) started numbering the years of the Islamic calendar from the year of the Hijra (Prophet's emigration from Makkah to Al-Madinah) The Islamic calendar has approximately 12 months and 354 days New day in the Islamic calendar starts at sunset. All Muslim holidays are based on the Islamic calendar. The 12 Islamic months in the Islamic calendar are Muharram, Safar, Rabi' al-awwal, Rabi' al-thani, Jumada al-awwal, Jumada al-thani, Rajab, Sha'aban, Ramadan, Shawwal, Dhu al-Qi'dah and Dhu al-Hijjah. Christian Calendar The Gregorian calendar is also sometimes referred to as the Christian or Western calendar The years in this calendar are based on Jesus's birth. So, according to Christians, "AD 2007″ literally means "in the 2007′th year since the birth of Jesus. There were other calendars introduced before the Gregorian calendar such as the Julian calendar. However, the Gregorian calendar sought to improve the earlier versions. The Christian calendar went through many changes with the last change named after Pope Gregory XIII The Gregorian calendar comprises of 12 months, and 365 days (366 days in a leap year). The months in the Gregorian calendar are of 30 or 31 days with February having 28 days and 29 days in a leap year. New day in the Gregorian calendar starts at midnight. Gregorian calendar forms the basis of the current day's calendar.