I'm not a historian and can't answer your question directly but here's just a tidbit of information that's hopefully of some use to you anyway: You don't absolutely need any kind of tuning instrument to tune a stringed instrument. The most vital part of the tuning ist, that the strings are tuned correctly relative to each other. Certainly there are some stringed instruments where it's easier and some where it's harder but it's definitely doable with all of them.

Take the guitar for exmaple: For standard tuning the low E string has to sound the same when pressed down at the 5th fret as the open A string. Every string can be tuned in this way. So, even if you don't have a perfectly tuned lower E string, you can just pick that one and tune all the other strings according to that one. Depending on how far of your lower E was, your songs will sound a bit higher or lower than "normal" but still in tune.

I'm a violinist. The note that an orchestra tunes to, A440 was only standardized around the turn of the 20th century. This is the pitch of a violin's A string. Before this pitch was standardized, different orchestras would tune to different pitches. As long as the orchestra all tunes to the same pitch, it really doesn't matter what that pitch is; everything that they play will be in tune relative to that pitch. I hope this answers your question somewhat. I can elaborate more if you'd like. I'm not a historian, though, just a musician with some knowledge of musical practice and history.