Leo XIII, 1878-1903

The Unity of the Church ¹

[From the Encyclical, "Satis cognitum," June 29, 1896]

1954. Surely, it is so well established among all according to clear and manifold testimony that the true Church of Jesus Christ is one, that no Christian dare contradict it. But in judging and establishing the nature of this unity various errors have led off the true way. Indeed, not only the rise of the Church, but its entire establishment pertain to that class of things effected by free choice. Therefore, the entire judgment must be called back to that which was actually done, and we must not of course examine how the Church can be one, but how He who founded it wished it to be one.

1955. Now, if we look at what was done, Jesus Christ did not arrange and organize such a Church as would embrace several communities similar in kind, but distinct, and not bound together by those bonds that make the Church indivisible and unique after that manner clearly in which we profess in the symbol of faith, "I believe in one Church." . . . Now, Jesus Christ when He was speaking of such a mystical edifice, spoke only of one Church which He called His own: "I will build my Church" [Matt. 16:18]. Whatever other church is under consideration than this one, since it was not founded by Jesus Christ, cannot be the true Church of Christ. . . . And so the Church is bound to spread among all men the salvation accomplished by Jesus Christ, and all the blessings that proceed therefrom, and to propagate them through the ages. Therefore, according to the will of its Author the Church must be alone in all lands in the perpetuity of time. . . . The Church of Christ, therefore, is one and perpetual; whoever go apart (from it) wander away from the will and prescription of Christ the Lord and, leaving the way of salvation, digress to destruction.

1956. But He who founded the only Church, likewise founded it as one; namely, in such a way that whoever are to be in it, would be held bound together by the closest bonds, so much so that they form one people, one kingdom, one body: "One body and one spirit, as you are called in one hope of your calling" [Eph. 4:4]. . . . Agreement and union of minds are the necessary foundation of so great and so absolute a concord among men, from which a concurrence of wills and a similarity of action naturally arise. . . . Therefore, to unite the minds of men, and to effect and preserve the union of their minds, granted the existence of Holy Writ, there was great need of a certain other principle. . . .

1957. Therefore, Jesus Christ instituted in the Church a living, authentic, and likewise permanent magisterium, which He strengthened by His