Final answer:
Muslims, led by Muhammad, returned to Mecca in 630 CE after winning key battles and signing a truce with Meccan forces. This established Mecca as the heart of the Islamic world and the site where Muhammad destroyed the idols of the Kaaba, enforcing the worship of the one God, Allah.
Step-by-step explanation:
Muslims returned to Mecca in 630 CE because Muhammad and his followers had won battles against forces from Mecca, and a truce had been signed. This victory allowed not only for their safe return but also marked the symbolic and physical reclaiming of Mecca as the center of the Islamic faith. During the period between 625-630 CE, there were several battles between the Meccan forces and Muhammad's Muslim community. Muhammad's success in Medina in attracting converts, and in securing a community that unified religious and political authority, set the stage for his eventual return to Mecca. Muhammad entered the holy sanctuary of the Kaaba, destroyed the polytheist idols, and reinstated the worship of Allah, thereby restoring the sanctity of Abraham's original house of worship and establishing Mecca as the holiest place in Islam.