On June 15, 1822, Jane Williams claimed to have seen a doppelgänger of her friend Percy Bysshe Shelley. Two, in fact. Mary Shelley described the episode in a letter:

She was standing one day … at a window that looked on the Terrace with [Edward] Trelawny — it was day — she saw as she thought Shelley pass by the window, as he often was then, without a coat or jacket — he passed again — now as he passed both times the same way — and as from the side towards which he went each time there was no way to get back except past the window again (except over a wall twenty feet from the ground) she was struck at seeing him pass twice thus & looked out & seeing him no more she cried — 'Good God can Shelley have leapt from the wall? Where can he be gone?' Shelley, said Trelawny — 'No Shelley has past — What do you mean?' Trelawny says that she trembled exceedingly when she heard this & it proved indeed that Shelley had never been on the terrace & was far off at the time she saw him.

Three weeks later, Shelley drowned in the Bay of Spezia.