The Power of White Witchcraft

‘Merlin, give me the strength to carry on.’

I found this prayer not in some medieval book or carved on the wall of an ancient castle but written in ballpoint pen on a page torn from a diary and left – along with scores of similar pleas – on an ancient pile of stones in the Forest of Broceliande in Brittany.

Archaeologists say that this is the grave of a Neolithic hunter, but local tradition says that in this forest dwelled Vivien, the Lady of the Lake of Arthurian legend, and that here, having seduced Merlin in order to learn his secrets, she ensnared him with his own spells. The stone pile is known as Merlin’s tomb, and each year hundreds visit the site to thank the wizard or to ask for his aid. When I visited the tomb, prayers – written on scraps of…