(CNN) -- Here is a look at what you need to know about the Islamic New Year.
Islamic New Year will begin on Thursday, October 15, 2015. Exact date varies depending on method used to determine start of new year: using local moon-sighting or using astronomical calculations for new moon.
Facts: The Islamic New Year begins on the first day of the first month of the Islamic calendar.
The first month of the Islamic year is called Muharram.
The Islamic New Year has been observed in this way since 622 A.D. when the prophet Mohammed fled from Mecca to Yathrib (now called Medina) to escape religious persecution.
This migration is called Hijra in Arabic, also spelled Hegira.
The Islamic calendar is based on the lunar year.
The Islamic calendar has twelve months but only 354 days.
The Islamic New Year is usually celebrated with low-key religious events.
The day is an official holiday in some Muslim countries, but is a regular working day in others.