The Icelandic Sagas, such as Gretter's, are full of magic and witchcraft.

It is by witchcraft that Gretter is first lamed and finally slain; one can see that Glam's curse, the Beowulf motif, was not really in the original Gretter story.
"Folk-medicine" is really a branch of magic in old days, even to such pioneers of science as Paracelsus.
Saxo's traditions note drinking of a lion's blood that eats men as a means of gaining might and strength; the drinking of bear's blood is also declared to give great bodily power.
The tests for "madness" are of a primitive character, such as those applied to Odusseus, who, however, was not able, like Hamlet, to evade them.
The test for death is the red-hot iron or hot brand (used by the Abyssinians of to-day, as it was supposed in the thirteenth century to have been used by Grimhild.

"And now Grimhild goes and takes a great brand, where the house had burnt, and goes to Gernot her brother, and thrusts the burning brand in his mouth, and will know whether he is dead or living.

But Gernot was clearly dead.

And now she goes to Gislher and thrusts the firebrand in his mouth.