The early Church was under attack from false teaching which occurred from time to time and the term which was used for false teaching was called heresy. Heresy has been defined by R.C. Jones as an opinion or doctrine not in line with the accepted teaching of the church ,the opposite of orthodoxy. More so heresies which were common during the fifth century include Gnosticism, Neo-Platonism, apollinarianism ,arianism ,docetism ,Ebonism, Eutychianism and Nestorians. The above heresies very popular in first century to the fifth century and some continue to influence some church leaders because doctrines vary with different teachings. Therefore the essay will explain the above heresies in detail since heresies dominated the early church in first century.
Many bishops in early church had experienced many heresies because the main function of heresy was to divert Christians from what they believed or the true doctrine .Gnosticism was one of the heresy which preached among the people .They believed in salvation through gnosis and viewed Christ as a great prophet according to R.C. Jones. Therefore Christian doctrine states that salvation came through Jesus Christ while Gnosticism preached that it was through knowledge which was against what the Christian foundation was laid off. More so this heresy was destroying what Christ had done for humanity because this heresy viewed Christ as a great prophet not as Christ the messiah whom Christians had embraced as the son of God .Also the above teaching was in great contradiction with what the apostles had been preaching long back because the new testament states that it was not through works that one could be saved but by the grace of God not knowledge .One can argue that Gnosticism was a heresy to Christians which shook peoples believes .
In addition Neo-Platonism which was taught in the first century AD which was heresy because it states that the body of human was a prison to which the soul is trapped inside. Neo-Platonism was about the fact that human strive for freedom from prison from the body and that reincarnation is possible for the spirit not released at death according to C.R. Jones. Therefore the neo Platonist believed that reincarnation was possible a heresy to Christians because Christians does not believe in reincarnation .More so Christians viewed the human body as the temple of the lord not prison and this is supported by the fact people had been created in the image of God .This shows why the Neo-Platonism was such a heresy in the first century BC because Christians does not view the human body having control over their souls but they viewed the body as vessel which must be used for the glory of God .One can argue this heresy was launched as a result of the influence of Greek philosophy.
Furthermore appollinarianism was another heresy which was popular in 310 to 390 AD which denies the completeness of Christ humanity .Apollonarius developed world flesh Christology even further and said that God did not conjoin with man but only with flesh according to M.J.Erickson. Erickson .This shows that apollonarius heresy was against the basis of Christianity which give one no doubt why it was rejected by the church authority. Therefore this heresy goes on to states that a person has one nature Christ had conflicting nature .This was heresy in the sense that Christian believed that Christ was a son of God and Christ was God himself through the trinity while in contrary the heresy was stating that no one can have two nature if one does nature will conflict itself and if so then Christ was myth not a real person. Also Christians believed that since Christ was son of God who was sent to be sacrificed which was not the apollinarianist were teaching .one can argue that apollinarianism was a heresy which against the spreading of Christianity to the whole world.
More so Arianism was another heresy which was popular in early centuries AD which threatened Christ work of redemption and atonement .This was defended that salvation in Christ is only possible if the low is truly God, a mere creature cannot redeem just as he cannot create according H.D.Macdonald.Arianism denies that the father made the son out of nothing who made the world therefore one can argue that this was against the doctrine of Christianity which states that the God and Christ are one .This mean that the arianism did not believe that Jesus Christ could actually offer salvation since Christ himself could not create life or create himself. Therefore this heresy shift the focus of the salvation through Jesus since god was not in Jesus which means the heresy claims that the salvation was incomplete in Jesus Christ .one can actually argue that the arianism heresy it came to denotes a divination from the religious norm which why a defence was made which states that salvation was through Jesus Christ.
In addition heresy known as eutychianism which denies two nature of Christ which mean that Christ was portrayed as myth because nothing exist with conflicting nature according to this heresy. He taught that Christ had two natures before but only one nature after the incarnation and the human nature was exalted or lost in the divine like a drop of honey in the ocean according to Charles Hogde.This shows that this heresy denies that Jesus was only human which was not true according to church doctrine which mean that teaching was diverting Christians from the truth. More so Nestorianism which speculates the nature of Christ as being conflicting since Christ had two natures. Nestorianism denies the unity of the two natures of Christ in one person and Nestorius went too far saying that Christ had two natures hence he was two people according to Charles Hogde. Therefore this teaching was against what the apostles had fought for which explains why it was called heresy.
Furthermore Monarchism generally refers to one ruler this was a heresy was the belief that godhead was singular therefore one divine monarch .Also it arose in the second century by the orthodox who wanted to maintain monotheism .The form of monarchism heresy stated that Jesus was a mere man who was adopted by God as his power according to Jeffrey Khoo. Some scholars have argued that this heresy contradicted with the doctrine of orthodox that of trinity which mean the heresy had some errors and was only supporting the monarchs which means that why it was attacked. Christ was the son of God even before the world was created Col 1:13-17.This bibles evidence shows that the monarchism heresy was wrong in the sense that Jesus was not a mere man but was the son of God even before the world was created which means that Jesus was God and this was hard for the people who propounded the monarchism heresy.
All in all heresy was any doctrine which contradict with the church and the fact that in first century to the fifth a lot of heresies were practised which include Gnosticism, Neo-Platonism, apollinarianism ,arianism ,docetism ,Ebonism, Eutychianism and Nestorians. Therefore some were argued against by church fathers.
Erickson.M.J, The Word Became Flesh: A Contemporary IncarnationalChristology (Grand Rapids: Baker, 1996),
McDonald.H.D, “Development and Christology,” Vox Evangelica 9 (1975):16, n. 97
Kings James Versions, Roman 13 ,Christian Art Publishers,Vereening,RSA,1930
 Millard J. Erickson, The Word Became Flesh: A Contemporary Incarnational
Christology (Grand Rapids: Baker, 1996), P. 58.
 H. D. McDonald, “Development and Christology,” Vox Evangelica 9 (1975):
16, n. 97.
 Kings James Versions, Roman 13 ,Christian Art Publishers,Vereening,RSA,1930