Ismailis are a branch of Shia Islam. They share many core beliefs with other Shia Muslims, including the belief that Ali ibn Abi Talib was the rightful successor to the Prophet Muhammad. However, Ismailis differ from other Shia groups in their interpretation of the line of Imams, the spiritual and political leaders of the community.
Ismailis believe that the Imamate passed from the sixth Imam, Ja'far al-Sadiq, to his son Ismail, rather than to Ja'far's older son Musa al-Kadhim, as Twelver Shias believe. This difference in understanding of the Imamate lineage is the primary distinction between Ismailis and other Shia groups.
