The flight of Mohammed from Mecca, September 13, a. d. 622 (subsequently established as the first year of the Moslem era); hence, any flight or exodus regarded as like that of Mohammed.
The expatriation of the Prophet Muhammad (Peace be upon Him) when he left Mekka for Yathrib, which became Medina (Medinat al- Nabi), the city of the Prophet. This event took place in 622 AD and marked the birth of the Islamic era.
the flight of Muhammad from Mecca to Medina in 622 which marked the beginning of the Muslim era; the Muslim calendar begins in that year