In the times of the Church Fathers the notion of heresy was related to the false doctrine what became the cause of derogations from the unity of the Church. It was a false tenet about God, hence the Fathers of the Church tried to define not only mistakes created within the Church, but also to develop orthodox doctrine. Due to the vastness of the this subject authors and texts defining heresies were selected. Firstly, attention was drawn on the Greek term a†resij contained in pagan literature and the writings of the New Testament, which allowed to see what was the impact, especially the biblical definition of heresy, on the understanding of the early Christian writers, especially before the first Council of Nice in 325. It was also necessary to ask about the origin of heresy and its characteristics. Fathers affirmed unequivocally that their creation were associated mainly with making the wrong choices. The result of this were incorrect relations of heretics to the truth and to the Church, wrong image of God and abiding in stubbornness. Fathers also attempted to define more precisely the scope of meaning of schism and heresy, which are concepts often used as synonyms.