The Persian faith of Baha'i (5 letters) is a monotheistic religion founded in the 19th century by Bahá'u'lláh. It emphasizes the spiritual unity of all humankind and encourages its followers to work for the betterment of society. Baha'i is one of the fastest-growing religions in the world, with adherents in more than 200 countries and territories. The core beliefs of the faith include the oneness of God, the oneness of humanity, and the oneness of religion. Baha'i also teaches that all religions are valid and that each has its own truth.