Who are Muhammad, Abu Bakr, and Ali, and what was their role in the Islamic faith?

What will be an ideal response?

Essay responses should include these points:
Islam was founded by the Prophet Muhammad.
Under four of Muhammad's associates, Muslim armies conquered Persia, Egypt, and the Byzantine provinces of Syria and Palestine.
The last caliph was Ali, who ruled from 656–661.
After Muhammad's death, his father-in-law Abu Bakr became the first caliph.
The power struggle after Ali's death resulted in the division of communities into Sunni and Shi'ite.