
What did the Watchtower say would happen in 1874?
The first of many key dates that formed the Watchtower’s initial doctrines was that of 1874. It was this date that they believed and taught Jesus’ invisible returned to earth to set up his new Kingdom.
1874: The Return of Jesus Christ. The book Prophecy (1929) page 65:
1874: The Return of Jesus Christ. The book Prophecy (1929) page 65:
“The Scriptural proof is that the second presence of the Lord Jesus Christ began in 1874 A.D.” This date later changed to 1914.
This proof is specifically set out in the booklet entitled Our Lord's Return.
This proof is specifically set out in the booklet entitled Our Lord's Return.
The Harp of God. 1928.

But now we are in the end of this Gospel age, and the Kingdom is being established or set up. Our Lord, the appointed King, is now present, since October 1874, A. D., according to the testimony of the prophets, to those who have ears to hear it: and the formal inauguration of his kingly office dates from April 1878, A. D. : and the first work of the Kingdom, as shown by our Lord, in his parables and prophecy (the gathering of "his elect"), is now in progress. "The dead in Christ shall rise first," explained the Lord through the Apostle; and the resurrection of the Church shall be in a moment.
Millennial Dawn, vol. 4: The Day of Vengeance. Page 621.

The most important thing to which all the prophecies point, and for which the apostles looked forward, has been the second coming of the Lord. It is described by the prophet as a blessed time. Daniel then says: “blessed is he that waiteth, and cometh to the thousand three hundred and five and thirty [1335] days.” Daniel 12:12 The watchers here are, without question, those those who were instructed by the Lord to watch for his return. This date, therefore, when understood, would certainly fix the time when the Lord is due at his second appearing. Applying the same rule then, of a day for a year, 1335 days after 539 A.D. brings us to 1874 A.D., at which time, according to biblical chronology, the Lord’s second presence was due. If this calculation is correct, from that time forward we ought to be able to find evidence, marking the Lord’s second presence.
Creation 1927 p319