I'd guess most of these are from the Luzon area of the Phillipines, and date from 1900-1950. But I'm always glad to be corrected.
I like the feel of these handles so much I modeled this handle after one. Doesnt look quite the same, but feels it. Incidentally, this handle is much nicer on a weight forward, heavier knife or short swort, like the old examples we've been showing. Isnt as good on a shorter blade like what I did