Iron Age or Roman Sword

[Bob A]

I con't comment on the sword, but the textile fragment must certainly be considerably more recent. don't think it could survive contact with iron oxide for a prolonged period without disintegrating.

My experience of iron-based dyes on wool - used to create a black color in the pile - is that wool so treated would become so brittle that it would wear down to the warp and weft over several decades.

Not much help, alas.