I still insist that I don't collect cameras. Or lenses. And then I couldn't let this one go without putting in a bid...
From what I can find out, it was made between 1898 and 1904. Der Herr Doktor Hans Schmidt, in "Photografisches Hilfsbuch für ernste Arbeit" (Berlin 1910), reports a total angle of illumination of 100 degrees - which for this 15cm lens (source: Dr. Schmidt again) should just about cover the 18x24cm film format of my equally ancient German folding camera.
I just wanted to gloat a bit