Shi'a Islam was established soon after the death of the second caliph, while Shi'a theology, governments and society emerged later, in the second and third centuries. It is the second largest denomination of Islam, after Sunni. These Shi'a people attribute themselves to the Qur'an and the teachings of Muhammad, and reject the legitimacy of the first three Rashidun caliphs. Although a minority in the Muslim world, Shi'a Muslims constitute the majority of population in Iran, Iraq, Azerbaijin and Bahrain.