This proposition has its proximate justification in that clear expression of the will of Jesus Christ, the founder of the Church, in which he designates the Apostle Peter as the rock on which he will build his Church. Moreover, it is precisely this rock-foundation which is to make the Church indestructible. [Footnote 8] From this it follows that, in virtue of the ordinance of Jesus, the office of Peter, or the primacy given him in the Church, was not to expire with the death of the apostle. For, if the {97} Church is indestructible precisely on account of her foundation upon the rock-man Peter, he must remain for all time the support of the Church, and historical connection with him is the indispensable condition on which the Church can be firmly established in any part of the earth. This constant connection with the Apostle Peter is maintained through the bishop of Rome for the time being. For these two offices, the episcopate of Rome and the primacy, were connected with each other in the person of the Apostle Peter. Consequently the same superior rank in the Church which Peter possessed is transmitted to the legitimate bishop of Rome at the same time with the Roman episcopal see. Thus the Prince of the Apostles remains in very deed the rock-foundation of the Church, continually, in each one of his successors for the time being. [Footnote 8: Matt. xvi. 18.] In the view of Christian antiquity, the unity of the Church was the particular object for which the papacy was established. [Footnote 9] This unity, apprehended in its historical development, gives us the conception of catholicity. [Footnote 10] [Footnote 9: St. Cyprian, _De Unit Eccl. Primatus Petro dafur, ut una Christi ecclesia et cathedra una monstretur_. The primacy is given to Peter, that the Church of Christ may be shown to be one, and the chair one.] [Footnote 10: Ibid. _Ecclesia quoque una est, quae in multitudinem. latius incremento faeccunditatis extenditur.... ecclesia Domini luce perfusa per obem totam radios suos porrigit. Unum tamen lumen est, quod ubique diffunditur, nec unitas corporis separatur._ The Church also is one, which is extended to a very great multitude by the increase of fruitfulness . . . the Church of the Lord pervaded with light extends its rays over the whole world. Nevertheless the light which is everywhere diffused is one, and the unity of the body is never separated.] Both these marks of the Church must embody themselves in the form of an outwardly perceptible historical reality. The Church being indebted for her unity, and by necessary consequence for her catholicity, precisely to her historical connection with Peter, catholicity is thus rooted in the idea of the papacy. But does its ultimate and most profound principle lie therein?