One attempt at a religion that emerged out of Shi'ite Islam in the 19th century was Baha'ism, which preaches a complete doctrine of perennial truth. According to Baha'i teaching, all religions carry the same truth, ranging from Hinduism and Zoroastrianism to Islam and the Baha'i faith itself. This was a development from the Islamic doctrine that Judaism and Christianity were early forms of one religion, Islam. Unlike Muslims, Baha'is do not believe in the Qur'anic doctrine of tahrif, which states that the Old and New Testaments were corrupted by rabbis and priest. It is questionable whether Baha'ism has been accepted as a mainstream religion and none of the mainstream proponents or prolific writers on Perennial School of Philosophy have been Baha'is. One of the requirements for the faith is to be one of angelic/divine nature and to have a record of spiritual transformation of individuals.