Early Christian thinkers developed the widespread linguistic cosmology of the Roman Mediterranean in a novel way in order to advance a specific bibliographic project: aligning the emergent fourfold Gospel with the structure of the physical cosmos. Employing interlocking concepts from the disciplines of meteorology, geography, music, mathematics, and astronomy, a number of figures—including Irenaeus, Origen, Ephrem, Eusebius, Fortunatianus, Augustine, and Maximus—imagined a Gospel corpus consisting of precisely four texts. Number provided a way to articulate the coherence of the fourfold Gospel—both with itself and with the rest of the world. By situating both familiar and neglected evidence in the context of ancient cosmology, I argue that early Christians theorized a divinely ordained correspondence between fourfold Gospel and quadriform cosmos.