1874, 1914 and the 10 Virgins

In the book "God's Kingdom of a Thousand Years Has Approached", published by the Watchtower Society in 1973, on page 209-210, para. 55 they explain that it was with the publishing of the book "Let God Be True" in 1943, that the 1874 date for the beginning of Christ's "invisible presence" was done away with and replaced with the 1914 date. ...