Every year, Muslims around the world celebrate the beginning of the New Islamic Year, which commemorates the occasion of Hijrah, or the Prophet Mohammad and his followers' migration from Mecca to Medina in 622 AD.
The Islamic calendar differs from the widely used Gregorian calendar as Muslims follow the lunar calendar consisting of 12 months in a year of 354 or 355 days, meaning that Muslims every year mark major calendar dates like Ramadan and Eid earlier each year.
It was during the era of Muslim leader Omar ibn al-Khattab when the Hijri calendar was established. It was narrated that al-Khattab had consulted the companions of the prophet on choosing from three events to mark the beginning of the Islamic calendar.
The options were the day and year of Prophet Mohammad’s birth, death or Hijra (migration) to Medina. The companions agreed on using the date of the Prophet’s Hijra.
The agreement on this matter was reached in the year 17 of the Hijra, the fourth year of the Omar ibn al-Khattab’s caliphate which corresponds to year 622 on the Julian calendar.
The Hijra to Medina was a turning point in Islamic history, marking the beginning of the Muslim state, and where the Prophet established the first civil Muslim society.
At first, there were discussions on whether the first month of the year should be Ramadan, the Muslim fasting month, or Muharram. Muharram was then announced as the first month of the Islamic Hijri calendar given that it comes after Muslims conclude the annual pilgrimage season to Mecca for Hajj during the month of Dhul Hijjah.
The exact date when the new Islamic Hijri New Year begins is calculated by different techniques, including via astronomical calculations, or via an official moon-sighting exercise similarly used during the sighting of the Ramadan crescent and Eid moons to determine those Islamic months.