Book 5 — Chapter 20 - Irenaeus against the Roman Schism
Book V centers on the persecution in Lugdunum and Vienna, Irenaeus, the Phrygian prophetic movement, Roman successions, and the major dispute over the date of Pesach. Eusebius's library work is central here. He names books, quotations, disputed writings, teachers, and chains of reception, often preserving information about works that later disappeared. In this reconstruction the chapter coordinate is preserved as Book 5, Chapter 20, and the full subject is retained under the heading 'Irenaeus against the Roman Schism'. Names, dates, quoted-source relationships, and political or textual function are kept distinct from Eusebius's own interpretive claims.