*The event where Muhammad fled Mecca with a small group of followers to go to Medina (Yathrib) in the year 622 A.D., under mounting hostility towards Muhammad. ***Muslim calendar starts from this date (A.H.), which was established in `Umar's reign. Medina is about 200 miles north of Mecca. Muhammad arrived there on 20th Sep 622 A.D. The name of the city was changed to Medinatu'l-Nabi (city of the Prophet).