1. A. Diem, ‘Was bedeutet Regula Columbani?’, in M. Diesenberger and W. Pohl, eds, Integration und Herrschaft. Ethnische Identitäten und soziale Organisation im Frühmittelalter (Vienna, 2002), pp. 63–89.
2. Columbanus, Regula monachorum and Regula coenobialis, ed. and trans. G.S.M. Walker, Sancti Columbani Opera (Dublin, 1957), pp. 122–69. In Benedict of Aniane’s Codex regularum, the first part of the Regula Columbani (which we call Regula monachorum) is titled Regula coenobialis; the second part (which we call Regula coenobialis) is simply called Paenitentialis eiusdem. Most manuscripts use the title Regula Columbani for both texts together.
3. On confession, see Rule of Ailbe, cc. 10 and 29, trans. U. Ó Maidín, The Celtic Monk. Rules and Writings of Early Irish Monks (Kalamazoo, 1996), pp. 20, 24; Rule of Ciarán, c. 16 (ibid., p. 47); Rule of Cormac Mac Ciolionáin, c. 6 (ibid., pp. 55–6); Rule of Carthage, c. 18 (ibid., p. 67); Rule of the Céli Dé (ibid., pp. 86, 88–9); Rule of Tallaght, cc. 20–2 (ibid., pp. 105–6); Columbanus, Paenitentiale B, c. 30, ed. Walker, p. 180.
4. See, for example, R. Meens, Penance in Medieval Europe, 600–1200 (Cambridge, 2014).
5. Canones Hibernenses II, cc. 3–4, ed. Ludwig Bieler, The Irish Penitentials (Dublin, 1963), p. 164; Canones Wallici, c. 34, ibid., p. 142.