They were thee for the steel ingots to make Ulfberht swords.
https://www.youtube.com/watch?v=4PSZkb4OeUE
Windlass makes a very good copy of the Ulfbehrt.
https://m.youtube.com/watch?v=sQrkKmOWXxM
I have another Windlass sword bought through MuseumReplicas.com and it is built very well; hand hammered tempered oil quenched carbon steel, not only took out a small tree, but chopped out the roots with it and dragged the stump out ;) the sword was still perfect, very satisfied.