The "nut-brown/brown sword" is an interesting one, pavane, isn't it. We found it too. Many references to brown swords in the ballads. Sometimes it's a "bright brown sword". There are a few theories, we understand.

1. That it refers to a bronze sword. Unlikely because bronze swords haven't been used since the bronze age.
2. That acid was used as a finish. The blade was then polished to a shiny brown.

Don can you help with this one?
Cheers, Joy