This item has appeared before.
http://www.vikingsword.com/ubb/Forum1/HTML/000732.html
I looked at the piece on eBay and, since I had two sheaths, made bids on it as it was in better condition that the one that I have. Both sheaths are illustrated in the referenced address. Discussion in the topic brought out that the piece should be properly called a ceremonial weapon as it is utilixed iby a priest in the cremation ceremony to open the final crematory item (bull or what ever) in order to insert the corpse as part of the ceremony.