The Jesus-clubs reacted against Marcion's tiny list of sacred works. The invention of the codex, the book, brought the issue of the canon to the forefront. Melito, Tatian, Irenaeus, Eusebius, and Athanasius made the first attempts to list a sacred canon. The Christians struggled against Marcionites, Montanists, and Gnostics to define what they believed. I introduce the Shepherd of Hermas.