Michaelmas Day was formerly regarded with suspicion in Wales. It was credited with uncanny power. There was an old superstition that on this night the Cistfaens, or warriors’ graves, in all parts of the Principality were illuminated by spectral lights, and it was very unlucky to walk near those places on Michaelmas Eve or Night; for on those two occasions the ghosts of ancient warmen were engaged in deadly fray around their lonely resting-places. (C. D. and Family Collection.)
From Marie Trevelyan’s Folk-lore and folk-stories of Wales (1909).