Maybe you're a very serious professional violinist or a violist, and potentially
you think that this instrument never existed.
Because composers never used the term "da spalla".
The truth is, composers called it simply "Violoncello".
There is a lot of evidence for this in paintings, written documents, music.
“Everything new is actually well-forgotten old…”
Now that you know, what are you going to do?
Ignore the fact this is a part of Classical Music and continue doing your best to make sure it dies and never re-surfaces again?
Or make keeping Classical music fresh and alive and make this part of your mission as a professional in Classical Music even more?