PelagianismPelagianism is a belief that original sin did not taint human nature (which, being created from God, was divine), and that mortal will is still capable of choosing good or evil with no Divine aid, whatesoever. Thus, Adam's sin was "to set a bad example" for his progeny, but his actions did not have the other consequences imputed to Original Sin. Pelagianism views the role of Jesus Christ as "setting a good example" for the rest of us (thus, counteracting Adam's bad example). In short, humanity has full control, and thus full responsibility, for its own salvation in addition to full responsibility for every sin (the latter insisted upon by both proponents and opponents of Pelagianism).
It is debatable whether the monk and moralist Pelagius actually advocated such an extreme view. Pelagianism was opposed by Augustine of Hippo, leading to its condemnation as a heresy at several local synods, these condemnations summarily ratified at the Council of Ephesus, although it was not considered a major act of that council.
See also: Semipelagianism