Marcionism was an early heresy led by
Marcion, who proposed the first canon of Christian texts. The proposed canon consisted of the
Gospel of Luke and several of
Paul's epistles; however, Marcion edited the writings by deleting any references that appeared to approve of the
Old Testament and the creator God of the Jews. Marcionism thus rejected the Old Testament God, claiming that Jesus represented the true sovereign God who was different from the God of the Hebrew people.
Marcion's proposal for a "New Testament" helped to spur others to respond with other canons that retained the Hebrew scriptures and did not reject Christianity's Jewish heritage.
Athanasius, in response to Marcionism, recommended that the Church approve the 27 books which comprise the Christian New Testament.