Look for music in the public domain (expired copyrights), which should
cover the period you're researching, and unrestricted performance
shouldn't be a problem. If you find something from the right period in a
much later compilation with a new copyright, this copyright usually
restricts reproduction of the printed page, not performance. But then
check this out with your institution's legal counsel before you do
anything--but it must be someone with copyright experience. Even though
several lawyers actually have called me for copyright advice, I am not
claiming any expertise! --David Haberstich, Smithsonian Institution.