Joe, I'm not sure I buy your chronology of Yiddish music. Of course, we have no recording over 100 years old; we don't have any sheet music that old either, but the klezmers learned from their elders, not from sheet music. It is true that a lot of music comes from the Yiddish theater, which I think goes back only to 1880 or so, but surely there are traditional songs that go back farther. Absence of documentation is not documentation of absence....

And as for the question, how old is old, I have always felt, and expect to continue to feel, that anyone older than I am is old, and anyone younger than I am is young.