Marcion of Sinope
Marcion of Sinope, a bishop of Asia Minor who went to Rome and was later excommunicated for his views, may have been the first of record to propose a definitive, exclusive, unique list of Christian scriptures, compiled sometime between 130–140 AD. Whether his canon was preceded by that of the Church is debated. Though Ignatius did address Christian scripture, before Marcion, against the perceived heresies of the Judaizers and Docetists, he did not define a list of scriptures. In his book "Origin of the New Testament" Adolf von Harnack argued that Marcion viewed the church at this time as largely an Old Testament church (one that "follows the Testament of the Creator-God") without a firmly established New Testament canon, and that the church gradually formulated its New Testament canon in response to the challenge posed by Marcion.