(Greek aphthartos, “incorruptible”), a Christian heresy of the 6th century that carried Monophysitism (“Christ had but one nature and that divine”) to a new extreme; it was proclaimed by Julian, bishop of Halicarnassus, who asserted that the body of Christ was divine and therefore naturally incorruptible and impassible; Christ, however, was free to will his sufferings and death voluntarily. Severus (Severus Of Antioch), patriarch of Antioch, himself a condemned Monophysite, vigorously challenged Julian on the ground that the doctrine of salvation was meaningless unless Christ's body was truly human. The Byzantine emperor Justinian I proclaimed the new heresy in an edict of 564 and would have imposed it on the Eastern church but for his death the following year.