Blackman's important essay is a study of Marcion's relation to, and influence on, the developing Catholic Church. It considers Marcion's work as the organizer of a Christian church, as Biblical critic, canon-maker, textual emendator, and, finally, as theologian. Blackman attempts throughout to trace the effect of his work in the larger context of Catholic Christianity at that time, and thus to reach some estimate of Marcion's significance in the history of Christianity. While the work of Harnack obviously influences Blackman, the author asserts that Harnack over-estimated the significance of Marcion.
