The Iranian religion is composed of two main branches: Baha'i and Shia. Baha'i is a monotheistic religion founded in the 19th century by Bahá'u'lláh, who taught that there is one God and that all major religions are part of one divine plan. Shia Islam is the second largest branch of Islam and is the majority religion in Iran. It is based on the teachings of the Prophet Muhammad and his descendants, known as Imams.