An interesting and entertaining introduction to temperaments in the Renaissance (but which does not broach the subject of fretted instruments):
https://www.youtube.com/watch?v=R75unSXKJXQ&feature=youtu.be Some of the other episodes are also relevant to questions of temperament. Best, Matthew To get on or off this list see list information at http://www.cs.dartmouth.edu/~wbc/lute-admin/index.html