Hi! I don't rly know if theres a way to chat on these wiki's, so I'll just post it here.
I think you might have mixed up the Ring Cycle by Richard Wagner, which is BASED on norse/germanic mythology, with the actual mythology. You see, in the Ring Cycle or "Der Ring des Nibelungen", Brünhilde does indeed have a horse named Grane. However this character is not from the actuall mythology, but is just based on a character from mythology.
In norse mythology, Brynhildr is a valkyrie that has been condemned by Odin to live as a mortal, and lies within a ring of flames untill Sigurd rescues her. And in Germanic mythology, Brunhild is the queen of Iceland. But in none of these mythologies does she own a horse named Grani or Grane as far as I know.
Now I don't know too much about Germanic mythology so i can't be 100% sure, but since I'm scandinavian I know a bit of norse mythology, and Grani in norse mythology is the horse of the hero and dragonslayer Sigurd. He was given advice by the god Odin, when selecting a horse. Odin said that the horse was of Sleipnir's kin. Afterwards Sigurd named it Grani.
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