Twelver Shi'ism is the largest branch of Shia Islam. Twelver Shi'ism believes in the divinely ordained "Twelve Imams", and they believe that the last of the twelve imams disappeared and would return as the promised "Mahdi", whose tenure would coincide with the second coming of Jesus. Twelvers believe that the Twelve Imams are exemplary human individuals, that they were the spiritual and political successors of Muhammad, that Muhammad and the imams were free from error and sin, and that they must be chosen through Muhammad. 85% of all Shias, some 150-300 million people, are Twelvers, making majorities among Muslims in Iran, Azerbaijan, Iraq, Lebanon, and Bahrain. Alevis in Turkey and Albania and Alawites in Syria and Lebanon share belief in the Twelve Imams, but have differing theological doctrines.