I think the GCFADG renaissance tuning is mostly used for music written from about 1500 to around 1630 or so , when lutes only had up to 10 courses...a 13 course lute would be suitable to play Bach,Weiss,Gallot and other Baroque and Galant style composers which used the d minor tuning circa 1630 to the middle of the 18th century (when the lute, sadly , went out of style)...Scotty