According to Sunni accounts, Muhammad died without having appointed a successor, and with a need for leadership, they gathered and voted for the position of caliph. Shi'a accounts differ by asserting that Muhammad had designated Ali as his successor on a number of occasions, including on his death bed. Ali was supported by Muhammad's family and the majority of the Muhajirun, the initial Muslims, and was opposed by the tribal leaders of Arabia who included Muhammad's initial enemies, including, naturally, the Banu Umayya.[1] Abu Bakr's election was followed by a raid on Ali's house led by Umar and Khalid ibn al-Walid (see Umar at Fatimah's house).