Heresiarch

A heresiarch (also hæresiarch, according to the Oxford English Dictionary; from the Greek: αἱρεσιάρχης, hairesiárkhēs, literally "heresy chief") is a founder or leader of a heretical doctrine or movement, as considered by those who claim to maintain an orthodox religious tradition or doctrine.

The first official heresy of the Christian church, Arianism, was created by heresiarch Arius. It taught that Jesus was of lesser substance than God, and was rebuked by Constantine's First Ecumenical Council of Nicea, which asserted that Jesus and God the Father were "cosubstantial", i.e. of the same divine substance.

Heresy is a controversial or novel change to a system of beliefs, especially a religion, that conflicts with established dogma.[1] It is distinct from apostasy, which is the formal denunciation of one's religion, principles or cause,[2] and blasphemy, which is irreverence toward religion.[3] 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.

The word "heresy" comes from the Greek hairetikos:
"able to choose"...