Hi Brian,
Thanks for the link.
Still the examples shown in the article, besides smaller in dimensions, do not coincide much with the shape of this thread's example.
As for stratigraphy, i wouldn't think it would play a role here.This item was in possession of a local peasant; therefore much more probably an open air finding than a digging. You are right in that the place has seen the presence of several human stock; more likely inhabited by the first ones and only serving as a route by the late.
Certainly Galicians, dominated by Romans, succeeded by Suevos, removed by Visigods, you name them.
There is a well preserved Sauna bath complex in the area, showing Roman evidence.
Wellington and Napolean (Soult) troops might also have been around, but probably using the area as a passage, less possibly using it as a battle field, much less as a residence.
Considering this blade continued sharpening, i understand such action would consume the blade in a more extensive area towards the front, thus not leaving such a pronounced belly near the tip, as also it would remain wider in the back end, therefore with a rather different configuration; this assuming, as you say, that sharpening techniques didn't change over time.
... Unless its cutting utility was not practiced by a conventional butcher ... as much early in time as butchers existed.
Mind you, i am not, by any means, qualified in metalurgy or any sort of scholarship close to this problematic, to reject your suggestion all the way.
We are just brainstorming here
.
Until a similar item shows up or/and a categoric ID is attributed, anything is possible
.
Fernando