Adv. Hær. I. 27. 4, III. 12. 12. This promise was apparently never fulfilled, as we hear nothing of the work from any of Irenæus’ successors. But in Bk. IV. chap. 25 Eusebius speaks of Irenæus as one of those who had written against Marcion, whether in this referring to his special work promised here, or only to his general work Adv. Hær., we cannot tell.