This extract is introduced as follows: “For Irenæus Bishop of Lyons, who was a contemporary of the disciple of the apostle, Polycarp Bishop of Smyrna, and martyr, and for this reason is held in just estimation, wrote to an Alexandrian to the effect that it is right, with respect to the feast of the Resurrection, that we should celebrate it upon the first day of the week.” This shows us that the extract must have been taken from the work Against Schism addressed to Blastus.