Manicheism

Manicheism is the only world religion that has become completely extinct. Its founder, Mani, lived in the third century CE. His religion spread over the continents from the Atlantic to the Chinese Sea.
Manichaeism taught an elaborate dualistic cosmology describing the struggle between a good, spiritual world of light, and an evil, material world of darkness. Through an ongoing process that takes place in human history, light is gradually removed from the world of matter and returned to the world of light, whence it came. Its beliefs were based on local Mesopotamian gnostic and religious movements.
An adherent of Manichaeism is called, especially in older sources, a Manichee, or more recently Manichaean. By extension, the term "Manichean" is widely applied (often used as a derogatory term) as an adjective to a philosophy of moral dualism, according to which a moral course of action involves a clear (or simplistic) choice between good and evil, or as a noun denoting people who hold such a view.
Manicheism probably died out in the European part of the Roman Empire in the 6th or 7th century, in Byzantium not later than in the 9th century, but probably already in the 7th century (Rochow, 1979, pp. 13-21), in the Islamic Near East in the 11th century, in Central Asia probably in the 12th or 13th century, and finally in China in the 16th century (Lieu, 1992, p. 303). A Manichean temple in Buddhist disguise still exists in Quanzhou in the South Chinese Fujian province (Bryder, 1988, pp. 201-8). It is true that European scholars recently discovered traces of Buddha-Mani worship still being practiced in the same Fujian province, but this is, according to S. N. C. Lieu, a modern revival of the faith once widespread in this region. The same may be true of a modern “Manichaean Church” presented on the internet (accessed 20 July 2009).
Wherever it was present, Manicheism appeared as the religion of an often persecuted minority, with the exception of the Huhui steppe empire and the Huihu kingdom of Qocho, where it gained the status of a state religion from about 762 to the 11th century.
In Xinjiang Chinese archaeological work is continuing and supplementing earlier European and Japanese excavations. A substantial quantity of Iranian (mainly Sogdian) and Old Turkish Manichean texts were discovered at Bezeklik.
Manicheism itself claimed the universal validity of its truth. Mani regarded his doctrine not as the religion of a region, a state, or a chosen people, but as the completion of the preceding great religions of Christianity, Zoroastrianism, and Buddhism.