Mani 240 - 277 A.D. Also known as Manes (Greek) or Manichaeus (Latin), or, if you're a believer, "the ambassador of light"
Mani was a Persian prophet, and the founder of Manichism. When a rich widow to whom Mani had been a servant died and left him her fortune, he embarked on an evangelical mission, founding a religion which tried to unite Zoroastrianism with Christianity. He was twice "visited by an angel: the Messenger of the light of Paradise," who told him to proclaim and spread the revelations he would be given. These revelations taught that human souls are prisoners of darkness, and that in order to reclaim their heavenly destiny the soul must deny and abandon the bodily prison. He believed in the monotheistic God, and considered Zoroaster, Buddha and "Jesus the illuminated one" to all be prophets of the one true God. He further believed that the world is split into a duality of good and evil, with evil having its own power (i.e. Evil is not just the absence of good, nor is Satan just a tool of God. Evil is an opposing force. This is an important distinction to many theologians, because it denies the existence of an all-powerful God. If God is opposed in any way, he must be somehow fallible.)
In 277, after returning to Persia from a pilgrimage to India, Mani was imprisoned and put to death by the Zoroastrian Magi of Bahram 1st. His followers were scattered, and his teachings spread to Egypt, Arabia, Africa and much of the Roman Empire, eventually working their way into the theologies of several cults, notably the Gnostics and the Cathars.
Mani's name appears in Catholic Encyclopedia as a heresiarch who tried to convert the Church Father Archelaus. And St. Augustine was a Manichaean before he became a Christian.