I'm working through some tunes by Byrd, and am wondering about the ornamentation, the two diagonal slashes through the note stem.
As far as I can tell, we don't actually know what the composers of that period meant by them, although there are some long and laborious extrapolations out there. They may be upper or lower mordents, or trills, and left out entirely or added according to the taste of the performer.
Is that about right? Is there any guidance on how to approach them besides just doing what you think sounds good?