Hi! For starters, I'm Michele (/miˈkɛːle/) nice to meet you all! I'm new to the forum! I've read a couple of things around and I'm liking it very much!

So I'll jump straight to the question I have.
We all know the technique to force a protective patina on Carbon Steel through the application of vinegar, and that's really convenient (and cool) but I was wondering if it was ever done Historically during the middle ages or even before. I tried to search for accounts describing this technique or even advising it, but I'm pretty bad at researching.
have any of you found a reliable source where it proved this was actually done in the past?