"By divine Providence it has come about that various churches, established in various places by the apostles and their successors, have in the course of time coalesced into several groups, organically united, which, preserving the unity of faith and the unique divine constitution of the universal Church, enjoy their own discipline, their own liturgical usage, and their own theological and spiritual heritage. Some of these churches, notably the ancient patriarchal churches, as parent-stocks of the Faith, so to speak, have begotten others as daughter churches, with which they are connected down to our own time by a close bond of charity in their sacramental life and in their mutual respect for their rights and duties.(37* De iuribus Sedium patriarchalium, cfr. Conc. Nicaenum, I can. 6 de Alexandria et Antiochia, et can. 7 de Hierosolymis: Conc. I Oec. Decr., p. 8. Conc. Later. IV, anno 1215, Constit. V: De dignigate Patriarcharum: ibid. p. 212.-| Conc. Ferr.-Flor.: ibid. p. 504.) This variety of local churches with one common aspiration is splendid evidence of the catholicity of the undivided Church. In like manner the Episcopal bodies of today are in a position to render a manifold and fruitful assistance, so that this collegiate feeling may be put into practical application."
The Second Ecumenical Council of the Vatican, Dogmatic Constitution on the Church Lumen Gentium [Tipografia Poliglotta Vaticana, Citta del Vaticano] 1966, №. 23 pp. 29-30.