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Background (1870–1916)

In 1870, Charles Taze Russell and others formed a group in Pittsburgh, Pennsylvania, to study the Bible. During his ministry, Russell disputed many of mainstream Christianity's tenets, including immortality of the soul, hellfire, predestination, the fleshly return of Jesus Christ, the Trinity, and the burning up of the world. In 1876, he met Nelson H. Barbour. Later that year they jointly produced the book Three Worlds, which combined restitutionist views with end time prophecy.

The book taught that God's dealings with humanity were divided dispensationally, each ending with a "harvest", that Jesus had returned as an invisible spirit being in 1874, inaugurating the "harvest of the Gospel age", and that 1914 would mark the end of a 2,520-year period called "the Gentile Times", at which time world society would be replaced by the full establishment of God's kingdom on earth. Beginning in 1878, Russell and Barbour jointly edited a religious magazine, Herald of the Morning. In June 1879, the two split over doctrinal differences, and in July, Russell began publishing the magazine Zion's Watch Tower and Herald of Christ's Presence, saying its purpose was to demonstrate that the world was in "the last days" and that a new age of earthly and human restitution under Jesus' reign was imminent.

From 1879, Watch Tower supporters gathered as autonomous congregations to study the Bible topically. Thirty congregations were founded, and during 1879 and 1880, Russell visited each to provide the format he recommended for conducting meetings. In 1881, Zion's Watch Tower Tract Society was presided over by William Henry Conley, and in 1884, Russell incorporated the society as a nonprofit business to distribute tracts and Bibles. By about 1900, Russell had organized thousands of part- and full-time colporteurs, and was appointing foreign missionaries and establishing branch offices. By the 1910s, Russell's organization maintained nearly a hundred "pilgrims", or traveling preachers. Russell engaged in significant global publishing efforts during his ministry, and by 1912, he was the most distributed Christian author in the United States.

Russell moved the Watch Tower Society's headquarters to Brooklyn, New York, in 1909, combining printing and corporate offices with a house of worship; volunteers were housed in a nearby residence he named Bethel. He identified the religious movement as "Bible Students", and more formally as the International Bible Students Association. By 1910, about 50,000 people worldwide were associated with the movement and congregations reelected him annually as their pastor. Russell died on October 31, 1916, at the age of 64 while returning from a ministerial speaking tour.