C.T. Russell taught and borrowed the idea that each creative day was 7,000 years each, 7 x 7 is 49, thus the 50th would be the jubilee year that would eventually usher ion the Kingdom. He believe it began in 1872 or thereabouts.
Later the Judge made all these changes without explaining why. he moved the presence from 1874 to 1914, and made may other chronological chnages without any chronology to explainthe dates. It fell on the shoulders of red Franz to make sense of it all, this he did in 1966, when Franz wrote the "Freedom" book adding 102 years to the Chronology, from 1872 to 1975, claiming that teh end of 6,000 years would be in 1975 ushering in the 7,000th and everyone expecting armageddon, even some non-witness groups looked in 1975.
RR