Heresy is the rejection of one or more established beliefs of a religious body, or adherence to "other beliefs." Christian heresy refers to non-orthodox practices and beliefs that were deemed to be heretical by one or more of the Christian churches. In the West, the term "heresy" most commonly refers to those beliefs which were declared to be anathema by the Catholic Church prior to the schism of 1054. In the East, the term "heresy" most commonly refers to those beliefs declared to be "heretical" by the First Seven Ecumenical Councils. However, since the Great Schism and the Protestant Reformation, various Christian churches have also used the concept in proceedings against individuals and groups deemed to be heretical by those churches. The Catholic Church considers the Protestant denominations to be heretical and considers the Eastern Orthodox schismatics.

Historical examination of heresies focuses on a mixture of theological, spiritual, and political underpinnings to explain and describe their development. For example, accusations of heresy have been leveled against a group of believers when their beliefs challenged, or were seen to challenge, Church authority. Some heresies have also been doctrinally based, in which a teaching were deemed to be inconsistent with the fundamental tenets of orthodox dogma.

The study of heresy requires an understanding of the development of orthodoxy and the role of creeds in the definition of orthodox beliefs. Orthodoxy has been in the process of self-definition for centuries, defining itself in terms of its faith and changing or clarifying beliefs in opposition to people or doctrines that are perceived as incorrect. The reaction of the orthodox to heresy has also varied over the course of time; many factors, particularly the institutional, judicial, and doctrinal development of the Church, have shaped this reaction. Heresy remained an officially punishable offense in Roman Catholic nations until the late 18th century. In Spain, heretics were prosecuted and punished during the Counter-Enlightenment movement of the restoration of the monarchy there after the Napoleonic Era.

Adjective

heretical (comparative more heretical, superlative most heretical)

1. Of or pertaining to heresy or heretics.
2. (of ideas or views) Contrary to mainstream or accepted opinion.

• unorthodox

• Christological (5)
• Soteriological (0)
• Trinitarian (3)

• Adoptionism (5)
• Apollinarianism (4)
• Arianism (9)
• Docetism (4)
• Donatism (6)
• Ebionites (8)
• Encratites (3)
• Eutychianism (5)
• Gnosticism@ (80)
• Manichaeism (6)

• Marcionism (5)
• Monarchianism (6)
• Monophysitism (5)
• Monothelitism (4)
• Montanism (8)
• Nestorianism (5)
• Pelagianism (6)
• Sabellianism (4)
• Subordinationism (3)
• Tritheism (2)

• Society: History: By Topic: Social History: Religion: Ancient: Christianity (0)
• Society: Religion and Spirituality: Christianity: Church History: Early Christian Writings: Ecumenical Councils (16)

• Christian Heresy
  roman-empire.net
  Short descriptions of Gnosticism, Montanism, Monarchianism, Arianism, Apollinarianism, Nestorianism, Eutychianism and Pelagianism.
• A Short Guide to Ancient Heresies
  ignatiusinsight.com
  A list of heresies with short descriptions.
• Story of the Church - Early Heresies
  ritchies.net
  A list of heresies with some of the responses of the Church.