Irenaeus

Irenaeus, head of the Christian community at Lyon (Lugdunum) in Gaul after c. 177, was a central figure in the second-century debate stimulated in the Christian churches by gnosticism and by the teachings of Marcion. His principal writing on these subjects – the treatise now known as Against Heresies – was significant not only for its criticisms and denunciations of his opponents, but also for its contribution to (a) the churches’ development of authoritative norms of teaching and (b) their ‘theology’, i.e., their interpretation of these norms for catechetical purposes.

Richard A. Norris Jr., “Irenaeus of Lyon,” in The Cambridge History of Early Christian Literature, ed. Frances Young, Lewis Ayres, and Andrew Louth (Cambridge: Cambridge University Press, 2004), 45.