History of Shia Islam

Shia (/ˈʃiːə/; Arabic: شيعة‎ Shīʠah, from Shīʻatu ʻAlī, "followers of Ali") is a branch of Islam which holds that the Islamic prophet Muhammad designated Ali ibn Abi Talib as his successor (Imam).[1] Shia Islam primarily contrasts with Sunni Islam, whose adherents believe that Muhammad did not appoint a successor and consider Abu Bakr (who was appointed Caliph through a Shura, i.e. community consensus) to be the correct first Caliph.[2] Unlike the first three Rashidun caliphs, Ali was from the same clan as Muhammad, Banu Hashim.[3]

Adherents of Shia Islam are called Shias of Ali, Shias or the Shi'a as a collective or Shi'i individually.[4] Shia Islam is the second largest branch of Islam: in 2009, Shia Muslims constituted 10 - 13% of the world's Muslim population.[5] Twelver Shia (Ithnā'ashariyyah) is the largest branch of Shia Islam,[6] with 2012 estimates saying that 85% of Shias were Twelvers.[7]

Shia Islam is based on the Quran and the message of Muhammad attested in hadith, and on hadith taught by their Imams.[8][9] Shia consider Ali to have been divinely appointed as the successor to Muhammad, and as the first Imam. The Shia also extend this Imammah doctrine to Muhammad's family, the Ahl al-Bayt ("the people/family of the House"[10]), and some individuals among his descendants, known as Imams, who they believe possess special spiritual and political authority over the community, infallibility and other divinely ordained traits.[11] Although there are many Shia subsects, modern Shia Islam has been divided into three main groupings: Twelvers, Ismailis and Zaidis, with Twelver Shia being the largest and most influential group among Shia.[12][13][14]