Final answer:
Muhammad fled to Yathrib (later renamed Medina) during the Hijrah in 622 CE, marking a significant event that led to the creation of the Islamic calendar.
Step-by-step explanation:
During the Hijrah, in 622 CE, Muhammad and a group of his followers fled religious persecution in Mecca and sought refuge in Yathrib, a city 200 miles to the north, which would later be renamed Medina (meaning “the city of the Prophet”). The residents of Yathrib welcomed Muhammad and his community as they hoped that he could act as an impartial mediator in the disputes between the clans and families in their city. This pivotal event in the history of Islam represents the migration or exodus of Muhammad's early community, and the year of the Hijrah marks the starting point of the Islamic calendar, which is a lunar calendar.
Additionally, even before the Hijrah, some Muslims sought refuge across the Red Sea in the Christian Kingdom of Aksum (modern-day Ethiopia) under the protection of the Negus. Muhammad's migration to Medina is seen as a significant event because it transformed Islam from a relatively small religious group within Mecca to a broader community that rapidly grew under Muhammad's leadership. The Islamic lunar calendar begins from this point and dates are often denoted as AH (After the Hijrah).