Just to correct the signature to the above: that was really me, not the previously unknown fellow named But, who came out through my uncontrolled fingers.

And here's an idea about "Spanish" tuning. It tunes the top four strings of the guitar like the standard "G" banjo tuning. (Just as "Sevastopol" tunes the top four strings of the guitar like the banjo tuning I know as "Straight D.")

That suggests that these guitar tunings may originally have been borrowed from banjo tunings popular in the 1880s or before. Seems likely enough, since banjo pickers have long been accustomed to use dozens of alternate tunings, whereas relatively few guitarists ever tune outside of standard EADGBE.

I don't know how far back "Straight D" can be traced, but the standard G tuning for the banjo dates well back into minstrel show days. Should we then be looking in minstrel show history for the origins of these tunings that later got transferred to the guitar, perhaps by musicians who played both and (as I've been accused of more than once) tended to find themselves blurring banjo styles over into guitar and vice versa?

Bob (Mr. But also says hello.)