Thanks for this link Issybird !
What a find ! It does make sense if she had the plague she would be buried quickly. Also while reading The White Queen, in this book she and her mother used I guess mild magic or perhaps white magic. They also had to be very careful, if they were seen as witches they would have been burned at the stake. Especially during the Plague years. Travellers often passed corpses of accused witches on the side of roads as a warning. They blamed witchcraft for the plague.