Final answer:
The Prophet Muhammad's migration to Medina from Mecca changed Islam forever by establishing a new religious and political community, spreading the message of Islam more successfully, and leading to the conquest of Mecca.
Step-by-step explanation:
The Prophet Muhammad's migration from Mecca to Medina, known as the Hejira or hijra, had a profound impact on Islam. It not only marked the beginning of the Islamic calendar, but also solidified the establishment of a new religious and political community. In Medina, Muhammad was able to gather more followers, establish religious and political authority, and spread his message more successfully. The migration to Medina also led to the expansion of Islam across Arabia and beyond, as Muhammad's followers were able to conquer Mecca and convert the city to Islam.