so before yet one of these churches had fallen into possession of heretics,(230) before yet there was any disagreement between them, he singles out one for its superior principate, on account of which it was necessary for every church to agree with it, which he grounds on its descent from S. Peter and S. Paul, giving every link in the chain of succession during the hundred and ten years which had elapsed between their martyrdom and his own episcopate. He sees an especial prerogative lodged in that church as the means of securing the whole Church’s organic unity; and this prerogative is, that it is among churches what S. Peter and S. Paul were among Apostles;(231) as the first general western council expressed it, “in it the Apostles sit daily, and their blood without intermission bears witness to the glory of God.”(232) Thus the conception expressed by Irenæus, with the greatest emphasis and continual repetition, in order to refute heresy, is that all truth and grace are stored up in the one body of the Church; to which his doctrine of the Roman Primacy is as the keystone to the arch. For everything in his view depends on the unity, the intrinsic harmony, of the truth which he is describing as lodged in the episcopate: the means therefore of securing that unity are part of its conception. Accordingly, to see in its due force his statement that every church must agree with the Roman Church, it must not be severed from the context and taken by itself, but viewed in connexion with the argument as part of which it stands. If the Church is to speak one truth with one mouth, which is his main idea, she must have an organic provision for such a result, which he places in the necessary agreement of all churches with one: and this is his second idea, subsidiary to the first, and completing it. Irenæus by birth and education represents in all this the witness of the Asiatic churches; as bishop of Lyons, the churches of Gaul. A few years after Irenæus, Tertullian in a professed treatise against heresy lays down exactly the same principles. With him, too, the main idea is the possession of all truth and grace by the one Body which Christ formed and the Apostles established. This he thus exhibits: