Wikipedia's first sentence called it “a "theological or religious opinion or doctrine maintained in opposition”. Today it says “any belief or theory that is strongly at variance with established beliefs or customs”.
Measured, not asserted. Every count, date and revision on this page was taken from Wikipedia's own history and checked against the live article. The words quoted are theirs.
Machine-checked against the full current article on 2026-08-03.
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The opening as it read in 2005
Heresy , according to the Oxford English Dictionary , is a "theological or religious opinion or doctrine maintained in opposition, or held to be contrary, to the ‘catholic’ or orthodox doctrine of the Christian Church, or, by extension, to that of any church, creed, or religious system, considered as orthodox. By extension, [ heresy is an] opinion or doctrine in philosophy, politics, science, art, etc., at variance with those generally accepted as authoritative."1
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The opening as it stood in 2010 2 passages from the previous snapshot no longer appear
Heresy is a controversial or novel change to a system of beliefs, especially a religion , that conflicts with established dogma .It is distinct from apostasy , which is the formal denunciation of one's religion, principles or cause, and blasphemy , which is irreverence toward religion.The founder or leader of a heretical movement is called a heresiarch , while individuals who espouse heresy are known as heretics .Heresiology is the study of heresy.
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"Heretic" and "Heretical" redirect here.The Gospel (allegory) triumphs over Heresia and the Serpent .Church of King Gustaf Vasa , Stockholm, Sweden , sculpture by Burchard Precht .The burning of adherents of the pantheistic Amalrician sect in 1210, in the presence of King Philip II Augustus .In the background is the Gibbet of Montfaucon and, anachronistically, the Grosse Tour of the Temple .Illumination from the Grandes Chroniques de France , c. 1255-1260.Heresy is any provocative belief or theory that is strongly at variance with established beliefs or customs.A heretic is a proponent of such claims or beliefs.Heresy is distinct from both apostasy , which is the explicit renunciation of one's religion, principles or cause, and blasphemy , which is irreverence toward religion.The term is usually used to refer to violations of important religious teachings, but is used also of views strongly opposed to any generally accepted ideas.It is used in particular in reference to Christianity , Judaism , Islam and Marxism .In certain historical Islamic, Christian, and Jewish cultures, among others, espousing ideas deemed heretical has been and in some cases still is subjected not merely to punishments such as excommunication , but even to the death penalty.
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Belief or theory that is strongly at variance with established beliefs or customs "Heretic", "heretical", and "heresies" redirect here. The Gospel (allegory) triumphs over Heresia and the Serpent . Gustaf Vasa Church , Stockholm, Sweden , sculpture by Burchard Precht .The burning of the pantheistic Amalrician heretics in 1210, in the presence of King Philip II Augustus . In the background is the Gibbet of Montfaucon and, anachronistically, the Grosse Tour of the Temple . Illumination from the Grandes Chroniques de France , c. 1455–1460.Heresy is any belief or theory that is strongly at variance with established beliefs or customs, in particular the accepted beliefs of a church or religious organization. A heretic is a proponent of such claims or beliefs. Heresy is distinct from both apostasy , which is the explicit renunciation of one's religion, principles or cause, and blasphemy , which is an impious utterance or action concerning God or sacred things. The term is usually used to refer to violations of important religious teachings, but is used also of views strongly opposed to any generally accepted ideas. It is used in particular in reference to Christianity , Judaism , and Islam . In certain historical Christian, Muslim and Jewish cultures, among others, espousing ideas deemed heretical has been and in some cases still is met with censure ranging from excommunication to the death penalty.
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Belief or theory that is strongly at variance with established belief or customs Not to be confused with hearsay . "Heretic", "heretical", and "heresies" redirect here. The Gospel triumphs over Heresia and the Serpent . Gustaf Vasa Church , Stockholm, Sweden , sculpture by Burchard Precht . A statue in Vienna portraying Saint Ignatius of Loyola trampling on a heretic The burning of the pantheistic Amalrician heretics in 1210, in the presence of King Philip II Augustus . In the background is the Gibbet of Montfaucon and, anachronistically, the Grosse Tour of the Temple . Illumination from the Grandes Chroniques de France , c. Heresy is any belief or theory that is strongly at variance with established beliefs or customs, particularly the accepted beliefs or religious law of a religious organization.A heretic is a proponent of heresy.Heresy in Christianity , Judaism , and Islam has at times been met with censure ranging from excommunication to the death penalty. Heresy is distinct from apostasy , which is the explicit renunciation of one's religion, principles or cause; and from blasphemy , which is an impious utterance or action concerning God or sacred things. Heresiology is the study of heresy.
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The opening as it stood in 2025 2 passages from the previous snapshot no longer appear
Belief or theory that is strongly at variance with established belief or customs "Heretic", "heretical", and "heresies" redirect here. Saint Nicholas with Arius at the Council of Nicaea , at which he is said to have hit him; Arius was known for preaching that Jesus was created by God and has a lower status , a heresy in Trinitarian Christianity The burning of the pantheistic Amalrician heretics in 1210, in the presence of King Philip II Augustus . In the background is the Gibbet of Montfaucon and, anachronistically, the Grosse Tour of the Temple . Illumination from the Grandes Chroniques de France , c. Heresy is any belief or theory that is strongly at variance with established beliefs or customs, particularly the accepted beliefs or religious law of a religious organization. A heretic is a proponent of heresy. Heresy in Christianity , Judaism , and Islam has at times been met with censure ranging from excommunication to the death penalty . Heresy is distinct from apostasy , which is the explicit renunciation of one's religion, principles or cause; and from blasphemy , which is an impious utterance or action concerning God or sacred things. Heresiology is the study of heresy.
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Today
Wikipedia's first sentence called it “a "theological or religious opinion or doctrine maintained in opposition”. Today it says “any belief or theory that is strongly at variance with established beliefs or customs”. Read the current article and compare.
2005
2010
2015
2020
Oct '23
2025
Counts in the opening at each snapshot. Green: the word gained ground. Red: it was cut. Grey: no change.
What Wikipedia says this is
Every article opens by defining its subject. This one was redefined since 2005, and today's defining sentence is their current revision.
Then
a "theological or religious opinion or doctrine maintained in opposition
Now
any belief or theory that is strongly at variance with established beliefs or customs
Struck red text is no longer in the article; dotted amber text was rewritten. Every revision id links to Wikipedia's copy; the text shown is our own saved copy. Data: /data. Wikipedia text is CC BY-SA; quoted for the record; not affiliated with Wikipedia.