The Taiping Rebellion in Qing China between 1850 and 1864. It was started by a man called Hong Xiuquan who failed his mandarin examinations, fell into a psychosis of some kind, and came to believe he was the brother of Jesus. The cult he started was wildly successful and turned an entire province into a cultist theocracy before being quashed by the Qing.
The social media morass is something entirely different.
There is no precedent for the mass hysteria of something as dumb as Qanon. Dead presidents dead children emerging from the grave to save the world?
Oh wait...Jesus...David..rocks...easter.
Nvm.