Answer:
Leaders of Mecca opposed Muhammad's beliefs and attitudes. They were certain that spreading of new religion will undermine their authority and also their significance. Therefore they decided to force Muhammed leave the city to preserve their power.
Step-by-step explanation:
Because of this Muhammad had to flee Mecca and to settle in Medina. After gaining support there, he decided to go back in Mecca, where at the end he introduced his authority.