Manichaeism is the religion of Manes or Mani, which arose in Babylonia about the middle of the third century as one of the many sects classified under the name of Gnosticism. From its beginning through the fourth century it was most successful in spreading deep into Central Asia as far as Chinese Turkestan and establishing itself in many places of the West to Rome and especially Carthaga. Manichaeism retained a large following in the East, even under Mohammedan rule, until it was finally swept away during the thirteenth century by the Mongolian invasion of Asia. In the Byzantine Empire and in the West, Manichaesim was as a religion entirely wiped out by fierce persecution, surviving only under different names in the form of secret conventicles that later helped to support the new heretic movements entering Europe from the East during the eleventh and twelfth centuries.

Mani was born in a Persian village called Mardinu, near the site of the modern city of Baghdad, in 215 or 216 AD. His father was a native of Hamadan, and his mother came of the royal stock of the Parthian Arsacids. The father, a religious eclectic, was transferred to Babylon, which was at that time a part of the Parthian Empire. Mani, when about twenty years of age, was inspired by divine revelation and came forward as a prophet. Manes (Manichaeus) began preaching in about 240 AD, at Ctesiphon, near Baghdad, capital of the powerful Sasanian dynasties. His first notable appearance in public was on the coronation day of the Sasanian King Shapuhr I in 242 AD.

Although his preaching seemed to have met with favor for a time in Persia, the growing opposition of the Zoroastrian priests let Shapuhr some years later to banish Mani from the Persian realm. During a long period of exile, approximately twenty years, he preached his doctrines in the region of Northern India, Tibet, Chinese Turkistan and Khurastan. Mani, in 272 or 273 returned to Persia, met with royal consideration during the brief reign of Ormazd I (Hurmizd); but fell victim to the Zorastrian priests, who envied his success and had him executed in 273 or 274. The manner of his death was horrible. He was flayed alive, and the body then decapitated. His death, however, did not hinder the rapid spread of Mani's Faith. Though banned from Persia, Manichaeism was soon disseminated westward through Central Asia, reaching ultimately as far as China where, though always sporadic, definite traces of his doctrine as late as the seventeenth century were discovered.

Manes' religion is based on the concept of an eternal dualism between the Good and the Evil that brought the world into being and will remain the primary forces until its end. While claiming, like all the other prophets who arose during the third century, that he used reason to attain religious truth (gnosis), his approach was through a popular religious cosmogony based on myth; his version of the myth is that of a cosmic conflict between the Princes of Light (God and the Divine Messenger of Light) and the Demons of Darkness (the Devil, representing matter, and his Messengers, the Archons), whose realms originally were separated from each other but had become fused by an event described in Manichaen theology as "the seduction of the demons." Parts of the divine substance Light were stolen by the Demons and used by the Prince of Darkness to build the earth with its visible heaven and all animal and vegetable organisms and the inanimate objects contained in it. Man was thus made part of the Devil's realm. But to Adam and to his procreation came the divine message to free the imprisoned Light within themselves, thus helping in the general process of freeing the substance imprisoned in the visible cosmos and of restoring it to the realm of Light. Manichaeism conceives the process of nature, which must end in the complete absorption of Darkness by Light, as part of the spiritual process of man, which is to free himself from evil, which came into his reach with Eve, another creation of the Devil. The explanation of the existence of evil in this world, along with the revelation of the remedy for it, is the most important part of Manes' teaching. As to the revelation to man of his own true nature and of his function within the cosmic process, Manes recognized the part played by such religious teachers as Buddha, Zoroaster, and above all Jesus Christ. Jesus functions as a Messenger of Light, whose importance in bringing about final victory is only surpassed by Manes, the last and most universal of all Prophets. It can not be doubted that Manes, who called himself in his letters the "apostle of Jesus," looked toward Christianity as his most important source of inspiration and found in it the justification of his own mission to the world. He accounted Zoroaster's dualistic doctrine as the struggle between light and darkness, soul and matter to be the basis of the problem of good and evil. He found in the teachings of the gentle Buddha lessons for the conduct of life to be accepted everywhere by mankind.

Manichaeism for a long time was known exclusively from non-Manichaean sources, from Syrian, Mohammedan, and Western Christian writings against Manichaeism. At the end of the nineteenth century, however, various fragments of Manichaean literature were found in Chinese Tukestan, Turfan. The papyri found about 1930 in El Faiyum, Egypt, containing a Coptic translation of writings by Manes and his first disciples were much more informative, allowing the details in the founder's life as well as the content of his teachings.