Irenaeus of Lyons was a second-century bishop whose Against Heresies became one of the principal sources for the study of early Gnostic movements. Writing against teachings he considered divisive, he defended the unity of creation, the continuity of Scripture, apostolic succession, and the rule of faith. His theology of recapitulation presents Christ as the one who gathers, heals, and restores the whole human story.
Irenaeus is indispensable because he both opposed many Gnostic schools and preserved detailed evidence about them. For the Royal Art, he represents the necessary counterpoint between inner knowledge and catholic wholeness: the question of how revelation, tradition, embodiment, history, and redemption belong together in the one Work of Christ.