"The Great Disappointment." The Millerites were the forerunners of the DUmmies and KOmmies constantly predicting "The Day When Everything Finally Changed."
Russellites followed the Millerites. When their millenial event didn’t arrived they changed their name in embarrassment to Jehovah’s Witnesses. If you ask a Jehovah’s Witness today about the Russellites they will feign ignorance even if they know all about them. Of course, many JH’s are so ignorant that they are completely unaware of their embarrassing origins.