This showed up the other day on The Bonnefont Garden's web site: "The nettle has a long relationship with humankind, and has been exploited as a fiber, a food plant, and a medicine. Cloth woven from nettle is stronger than the linen made from the stems of flax; remnants survive from the Bronze Age, and the fabric was still produced in both Scotland and Denmark in the eighteenth century."
I had heard the story of the Seven Wild Swans, where a princess has to weave clothes out of nettles to break the enchantment on her brothers, but I'd forgotten that it could actually be done.
This is one of the better posts the Bonnefont Garden has put out. What's interesting to me, in addition to the information about nettle, are the excerpts from ancient and medieval sources.