One Flock Under One Shepherd BUT NOT One Fold

He [Christ] promised us one flock under one shepherd, but not one fold. The famous passage, John 10:16, has been mistranslated by the Latin Vulgate, and the error has passed into King James's Version. Christ's flock is one, but there are many folds, and there will be "many mansions in heaven."

 Schaff, Philip, "The Reunion of Christendom."
(Evangelical Alliance for the United States of America, Christianity practically applied: The discussions of the International Christian Conference held in Chicago, October 8-14, 1893, in connection with the World's Congress, Auxiliary of the World's Columbian Exposition, and under the auspices and direction of the Evangelical Alliance for the United States. The general conference (1894), New York: The Baker & Taylor Co., 1894, pp. 305-340 (, p. 316).)

1844: the Beginnings of the Bahai Faith, a movement to unite all religions

On May 23, 1844, there arose in Shiraz, Persia, a young man, Ali Mohammed by name, who declared Himself to be The Bab [the Arabic word for door or gate], or the forerunner of  "He whom God would Manifest"---a great teacher, Who was soon to appear with manifest signs of divine power, through Whose teachings the religious unity of all peoples would be accomplished.

Remey, Charles Mason, The New Day; the Bahai Revelation, a brief statement of its history and teachings, Chicago: Bahai Publishing Society, 1919, p. 14.

In the year one thousand two hundred and sixty [A. H.], when he [the Báb] was in his twenty-fifth year [Jamádí-ul-Úlá 5th, 1260 A.H. (May 23rd, 1844 A.D.) is the date given by the Báb himself in the Persian Beyán as that whereon his mission commenced.], certain signs became apparent in his conduct, behaviour, manners, and demeanour whereby it became evident in Shíráz that he had some conflict in his mind and some other flight beneath his wing. He began to speak and to declare the rank of Báb-hood. Now what he intended by the term Báb [Gate] was this, that he was the channel of grace from some great Person still behind the veil of glory, who was the possessor of countless and boundless perfections, by whose will he moved, and to the bond of whose love he clung.

Browne, Edward G., A Traveller's Narrative written to illustrate the episode of the Báb, Cambridge: The University Press, 1891, p. 3.

Spiritualism to Unite Christianity

[...] I believe that one of the ultimate results of this movement [Spiritualism] will be to unite Christianity upon a common basis so strong and, indeed, self-sufficient that the quibbles which separate the Churches of to-day will be seen in their true proportion and will be swept away or disregarded.

Doyle, Arthur Conan, The Edge of the Unknown, London: John Murray, 1930, p. 274.
(see also Doyle, Arthur Conan, "The Uncharted Coast," The Strand Magazine, 1920b, v. 60, July-Dec., pp. 253-260 (p. 258)).

The Point of Spiritualism

The question has often been asked: "What was the purpose of so strange a movement [Spiritualism] at this particular time, granting that it is all that it claims to be?" Governor Tallmadge, a United States Senator of repute, was one of the early converts to the new cult, and he has left it upon record that he asked this question upon two separate occasions in two different years from different mediums. The answer in each case was almost identical. The first said: "It is to draw mankind together in harmony and to convince sceptics of the immortality of the soul." The second said: "To unite mankind and to convince sceptics of the immortality of the soul."

Doyle, Arthur Conan, The Edge of the Unknown, London: John Murray, 1930, pp. 273-274.
(see also Doyle, Arthur Conan, "The Uncharted Coast," The Strand Magazine, 1920b, v. 60, July-Dec., pp. 253-260 (p. 258)).