which event marks the start of the islamic calendar
the Hijra
title: Islamic New Year text: Islamic New Year The Islamic New Year, also known as Arabic New Year or Hijri New Year ( ""), is the day that marks the beginning of a new Islamic calendar year, and is the day on which the year count is incremented. The first day of the year is observed on the first day of Muharram, the first month in the Islamic calendar. The first Islamic year begins in 622 Common Era (CE) with the emigration of Prophet Muhammad from Mecca to Medina, known as the Hijra. All religious duties, such as prayer, fasting in the month of Ramadan, title: Islamic calendar text: Islamic calendar (see section below) in which odd-numbered months have thirty days (and also the twelfth month in a leap year) and even months have 29. In Arabic, the "first day" of the week corresponds with Sunday of the planetary week. The Islamic weekdays, like those in the Hebrew and Bahá'í calendars, begin at sunset. The Christian liturgical day, kept in monasteries, begins with vespers (see vesper), which is evening, in line with the other Abrahamic traditions. Christian and planetary weekdays begin at the following midnight. Muslims gather for worship at a mosque at noon on "gathering day" (, meaning title: Islamic calendar text: the Coptic Calendar, because a lunar calendar is not suited for agricultural work. The Islamic calendar employs the Hijri era whose epoch was retrospectively established as the Islamic New Year of 622 AD/CE. During that year, Muhammad and his followers migrated from Mecca to Yathrib (now Medina) and established the first Muslim community ("ummah"), an event commemorated as the Hijra. In the West, dates in this era are usually denoted AH (, "in the year of the Hijra") in parallel with the Christian (AD), Common (CE) and Jewish eras (AM). In Muslim countries, it is also sometimes denoted as H title: Islamic calendar text: established custom of the Arabs at that time. The years of the Islamic calendar thus began with the month of Muharram in the year of Muhammad's arrival at the city of Medina, even though the actual emigration took place in Safar and Rabi' I. Because of the Hijra, the calendar was named the Hijri calendar. The first day of the first month of the Islamic calendar (1 Muharram 1 AH) was set to the first new moon after the day the Prophet moved from Quba' to Medina (originally 26 Rabi' I on the pre-Islamic calendar) i.e., Friday, 16 July 622 title: Islamic calendar text: months between 1 AH and 10 AH are uncertain; Western calendar dates commonly cited for key events in early Islam such as the Hijra, the Battle of Badr, the Battle of Uhud and the Battle of the Trench, should be viewed with caution as they might be in error by one, two or even three lunar months. This prohibition was mentioned by Muhammad during the farewell sermon which was delivered on 9 Dhu al-Hijjah 10 AH (Julian date Friday 6 March, 632 AD/CE) on Mount Arafat during the farewell pilgrimage to Mecca. The three successive sacred (forbidden) months mentioned by