To see one’s own ‘fetch’ or ‘wraith’ (or ‘astral body’, in the language of paranormal studies) has always been regarded as a death omen. John Aubrey, in his Miscellanies of 1696, has an anecdote illustrating this belief:
The beautiful Lady Diana Rich, Daughter to the Earl of Holland, as she was walking in her Father’s Garden at Kensington, to take the fresh Air before Dinner, about Eleven a Clock, being then very well, met with her own Apparition, Habit and every thing, as in a Looking-glass. About a Month after, she died of the Small-pox. And ’tis said, that her Sister the Lady Isabella (Thinne), saw the like of herself also before she died. This account I had from a Person of Honour. A third Sister, Mary, was married to the Earl of Breadalbane, as we are informed, and it is recorded that she also, not long after her Marriage, had some such warning of her approaching Dissolution.
However, the theme is rare in English folklore; it occurs chiefly in tales about people who rashly keep watch in a church porch to see the wraiths of those fated to die in the coming year, and are horrified to see their own form among them.