Eusebius in his Ecclesiastical History tells us that in addition to hisgreat work Against Heresies St Irenus wrote A Discourse inDemonstration of the Apostolic Preaching. This work was entirely lostsight of: no one seems ever to have quoted a word of it. But it hasquite recently reappeared in an Armenian manuscript together with Books IV and V of the greater work. The Armenian translation proves to be a fairly close rendering of the original Greek.