Rasputin is one of the legends of the Twentieth Century. He was definitely real, but has been imputed with supernatural powers since at leat 1890. A popular preacher in his native Russia, he came to international prominence in 1905 when he was summoned to the imperial palace to heal Prince Alexei. His success in doing so led to him having great influence over the Tsarina, and, it was rumoured, the Tsar.
There were rumblings against him from quite early on, but they only became truly serious as it became clear that Russia’s involvement in World War One was becoming increasingly disastrous. A group of aristocrats led by Prince Felix Yusupov, were alleged to have poisoned him with a dose of cyanide large enough to kill five people, then shot him in the head. Still not dead, Rasputin attacked Yusupov, and the conspirators clubbed him, tied him up and dumped the body in the Neva river.
It is unclear how much truth there is to this – the poisoning in particular has been disputed. He was definitely shot in the forehead and dumped in the river, and he definitely died. But his death, like his life, remains controversial and disputed.