This summary explains the issue of orthodoxy and heresy within Christianity.

When the Roman Empire recognized Christianity, there was a demand for unified doctrine, leading to the persecution of heresies. The criteria for determining heresy were the fundamental creeds established at councils such as the Council of Nicaea.


In the beginning, the concept of heresy existed in the Jewish tradition as well. As Christianity grew larger, differences in opinion led to violent persecution.


Emperor Constantine tried to mediate disputes within Christianity. At the two Councils of Nicaea, the doctrine of the Trinity was declared orthodox, and Arianism was declared heretical.


The Trinity refers to the teaching that the three aspects of the Father God, the Son God Christ, and the Holy Spirit are one. The Arians, who viewed Christ as a created being, were declared heretical.


Afterwards, teachings that did not conform to the fundamental creeds such as the Nicene Creed were considered heretical, and all except Athanasianism were banned. Heresies found refuge outside the empire.


By aligning with power, Christianity suppressed heresies and became the mainstream of European civilization. However, the concept of heresy also had an aspect of hindering the development of scholarship.