in order to unite with the souls of the perfect. They were anti-clerical and rejected baptism and the sacraments, believing that the passions could be overcome and perfection achieved through prayer. Many groups held dualistic beliefs, maintaining that reality was composed into two radically opposing parts: matter, usually seen as evil, and spirit, seen as good. Docetism held that Jesus' humanity was merely an illusion, thus denying the incarnation. Others held that both the material and spiritual worlds were created by God and were therefore both good, and that this was represented in the unified divine and human natures of Christ. The orthodox teaching, as it developed in response to these interpretations, is that Christ was fully divine and at the same time fully human, and that the three persons of the Trinity are co-equal and co-eternal. Legal suppression of heresies It was only after the legalisation of Christianity, which began under Constantine I in AD 313 that the various beliefs of the proto-orthodox Church began to be made uniform and formulated as dogma, through the canons promulgated by the General Councils. The first known usage of the term 'heresy' in a civil legal context was in 380 by the "Edict of Thessalonica" of Theodosius I. Prior to the issuance of this edict, the Church had no state-sponsored support for any particular legal mechanism to counter what it perceived as 'heresy'. By this edict, in some senses, the line between the Christian Church's spiritual authority and the Roman State's jurisdiction was blurred. One of the outcomes of this blurring of Church and State was a sharing of State powers of legal enforcement between Church and State authorities, with the state enforcing what it determined to be orthodox teaching. Within five years of the official criminalization of heresy by the emperor, the first Christian heretic, Priscillian, was executed in 385 by Roman officials. For some years after the Protestant Reformation, Protestant denominations were also known to execute those whom they considered heretics. The edict of Theodosius II (435) provided severe punishments for those who had or spread writings of Nestorius. Those who possessed writings of Arius were sentenced to death. Ecumenical councils Seven councils considered by main Christian denominations as ecumenical were convened between 325 and 787. These were mostly concerned with Christological disputes: The First Ecumenical Council was convoked by the Roman Emperor Constantine at Nicaea in 325 and presided