Sunni Islam is the largest denomination of Islam, followed by 87â90% of the world's Muslims, and simultaneously the largest religious denomination in the world. The word Sunni refers to those who observe the
Sunnah, referring to the traditions and practices of Muhammad. The differences between Sunni and Shia Muslims arose from a disagreement over the succession to Muhammad and subsequently acquired broader political significance, as well as theological and juridical dimensions. According to Sunni traditions, Muhammad left no successor and the participants of the Saqifah event elected Abu Bakr as the first caliph. This contrasts with the Shia view, which holds that Muhammad appointed his son-in-law and cousin Ali ibn Abi Talib as his successor.