Revising a theory first put forward in 1927 by the modernist Catholic priest Joseph Turmel, the author contends the letters of Ignatius of Antioch were in fact written by a follower of Apelles, the second-century one-time disciple of Marcion. He shows how the present text of the letters are the work of a proto-Catholic editor who, later in the same century, modified the letters to make them serviceable to his own community. In support of this new theory, Parvus examines the Ignatian letters for traces of Apellean doctrine as well as telltale signs of editorial additions and deletions. He also ventures a guess as to the identity of the Apellean author and the orthodox editor.
In the last chapter of the book Parvus considers how this new scenario for the Ignatian letters impacts our understanding of early Christian history and literature. In particular, he notes certain similarities between the Ignatian and Johannine literature, and he shows how an Apellean origin for the Gospel and Letters of John explains many of their puzzling aspects. The proto-Catholic church's acceptance of the Johannine writings in a modified form was, Parvus claims, part of a reconciliation of this church with former followers of Apelles.