Craig is correct about the fictional Welsh invention of the longbow. You can't patent something that has been in common use for centuries. It is not clear that the Welsh even used longbows before those serving England in the Hundred Years War were issued them. It is unlikely that Vikings used a fletching jig. Some Viking fletching is set on in a slight helix and birch tar was used to affix the fletching. Apply the hot birch tar and let cool. Bind the feathers, [usually three]with spiral binding. Adjust the feathers evenly, straight or helical. Then carefully heat to liquefy the birch tar and let cool again. Voila, Everything fused and a perfect job if you were careful not to singe the feathers.