While Ali was preparing Muhammad's body for burial and performing his funeral rites, a small group of approximately fourteen Muslims met at Saqifah.
There, Umar ibn al-Khattab pledged allegiance to Abu Bakr, who subsequently assumed political power.
The gathering at Saqifah was disputed by some of Muhammad's companions, who held that Ali had been designated his successor by Muhammad himself.

Relations between Abu Bakr and Ali may have become strained after this.
Following the gathering at Saqifa, Umar and his supporters were allegedly sent by the new Caliph to Ali's house where Ali, Fatimah, and some of their allies were gathered.
Several scholars, such as Al-Tabari and Ibn Qutaybah, relate that Umar threatened to burn the building down if Ali refused to acknowledge Abu Bakr's authority.
While the historian Al-Baladhuri states that the altercation never became violent and ended with Ali's compliance, some traditions add that Umar and his supporters forcibly entered the house, resulting in Fatimah's miscarriage of their unborn son Muhsin.
The Kitab Sulaym ibn Qays (attributed to Sulaym ibn Qays, but possibly a much later creation) concludes the incident with Ali being dragged out of the house with a rope tied around his neck.
These events have been disputed, with several early historical sources arguing that Fatimah's child Muhsin had died in early childhood rather than being miscarried.
Other sources add that Ali later willingly offered Abu Bakr his oath of allegiance and gave a praise-filled oration during his funeral.
Professor Coeli Fitzpatrick surmises that the story of the altercation reflects the political agendas of the period and should therefore be treated with caution.

Nevertheless, the issue of succession to Muhammad caused the Muslims to split into two groups, Sunni and Shia.
Sunnis assert that even though Muhammad never appointed a successor, Abu Bakr was elected first caliph by the Muslim community.
The Sunnis recognize the first four caliphs as Muhammad's rightful successors.
Shias believe that Muhammad explicitly named Ali as his successor at Ghadir Khumm and Muslim leadership belonged to him by dint of divine order.

According to Wilferd Madelung, Ali himself was firmly convinced of his legitimacy for the caliphate based on his close kinship with Muhammad, his knowledge of Islam, and his merits in serving its cause.
He told Abu Bakr that his delay in pledging allegiance (bay'ah) to him was based on his belief in his own claim to the caliphate.
Ali did not change his mind when he finally pledged allegiance to Abu Bakr and then to Umar and to Uthman but had done so for the sake of the unity of Islam, at a time when it was clear that the Muslims had turned away from him.
Ali also believed that he could fulfill the role of Imam without fighting.

At the beginning of Abu Bakr's caliphate, there was a controversy about Muhammad's endowment to his daughter, especially the oasis of Fadak, between Fatimah and Ali on one side and Abu Bakr on the other side.
Fatimah asked Abu Bakr to turn over their property, the lands of Fadak and Khaybar, but Abu Bakr refused and told her that prophets did not have any legacy and that Fadak belonged to the Muslim community.
Abu Bakr said to her, "Allah's Apostle said, we do not have heirs, whatever we leave is Sadaqa."
Together with Umm Ayman, Ali testified to the fact that Muhammad granted it to Fatimah Zahra, when Abu Bakr requested her to summon witnesses for her claim.
Fatimah became angry and stopped speaking to Abu Bakr, and continued assuming that attitude until she died.
According to some sources, 'Ali did not give his oath of allegiance to Abu Bakr until some time after the death of his wife, Fatimah, in the year 633.

He pledged allegiance to the second caliph, 'Umar ibn Khattab, and helped him as a trusted advisor. '
Umar particularly relied upon Ali as the chief judge of Medina.
He also advised Umar to set Hijra as the beginning of the Islamic calendar. '
Umar followed 'Ali's suggestions in political matters as well as religious ones.

'Ali was one of the electoral council
While Ali was preparing Muhammad's body for burial and performing his funeral rites, a small group of approximately fourteen Muslims met at Saqifah. There, Umar ibn al-Khattab pledged allegiance to Abu Bakr, who subsequently assumed political power. The gathering at Saqifah was disputed by some of Muhammad's companions, who held that Ali had been designated his successor by Muhammad himself.
Relations between Abu Bakr and Ali may have become strained after this. Following the gathering at Saqifa, Umar and his supporters were allegedly sent by the new Caliph to Ali's house where Ali, Fatimah, and some of their allies were gathered. Several scholars, such as Al-Tabari and Ibn Qutaybah, relate that Umar threatened to burn the building down if Ali refused to acknowledge Abu Bakr's authority. While the historian Al-Baladhuri states that the altercation never became violent and ended with Ali's compliance, some traditions add that Umar and his supporters forcibly entered the house, resulting in Fatimah's miscarriage of their unborn son Muhsin. The Kitab Sulaym ibn Qays (attributed to Sulaym ibn Qays, but possibly a much later creation) concludes the incident with Ali being dragged out of the house with a rope tied around his neck. These events have been disputed, with several early historical sources arguing that Fatimah's child Muhsin had died in early childhood rather than being miscarried. Other sources add that Ali later willingly offered Abu Bakr his oath of allegiance and gave a praise-filled oration during his funeral. Professor Coeli Fitzpatrick surmises that the story of the altercation reflects the political agendas of the period and should therefore be treated with caution.
Nevertheless, the issue of succession to Muhammad caused the Muslims to split into two groups, Sunni and Shia. Sunnis assert that even though Muhammad never appointed a successor, Abu Bakr was elected first caliph by the Muslim community. The Sunnis recognize the first four caliphs as Muhammad's rightful successors. Shias believe that Muhammad explicitly named Ali as his successor at Ghadir Khumm and Muslim leadership belonged to him by dint of divine order.
According to Wilferd Madelung, Ali himself was firmly convinced of his legitimacy for the caliphate based on his close kinship with Muhammad, his knowledge of Islam, and his merits in serving its cause. He told Abu Bakr that his delay in pledging allegiance (bay'ah) to him was based on his belief in his own claim to the caliphate. Ali did not change his mind when he finally pledged allegiance to Abu Bakr and then to Umar and to Uthman but had done so for the sake of the unity of Islam, at a time when it was clear that the Muslims had turned away from him. Ali also believed that he could fulfill the role of Imam without fighting.
At the beginning of Abu Bakr's caliphate, there was a controversy about Muhammad's endowment to his daughter, especially the oasis of Fadak, between Fatimah and Ali on one side and Abu Bakr on the other side. Fatimah asked Abu Bakr to turn over their property, the lands of Fadak and Khaybar, but Abu Bakr refused and told her that prophets did not have any legacy and that Fadak belonged to the Muslim community. Abu Bakr said to her, "Allah's Apostle said, we do not have heirs, whatever we leave is Sadaqa." Together with Umm Ayman, Ali testified to the fact that Muhammad granted it to Fatimah Zahra, when Abu Bakr requested her to summon witnesses for her claim. Fatimah became angry and stopped speaking to Abu Bakr, and continued assuming that attitude until she died. According to some sources, 'Ali did not give his oath of allegiance to Abu Bakr until some time after the death of his wife, Fatimah, in the year 633.
He pledged allegiance to the second caliph, 'Umar ibn Khattab, and helped him as a trusted advisor. 'Umar particularly relied upon Ali as the chief judge of Medina. He also advised Umar to set Hijra as the beginning of the Islamic calendar. 'Umar followed 'Ali's suggestions in political matters as well as religious ones.
'Ali was one of the electoral council 
Ali