Yes, Excelsior(a quality mark & possibly trademark) did come from Gußstahlwerke Witten, A.G.(Witten Cast Steel Works with Witten of course as the city) founded and owned by Louis Constans Berger. It was a crucible steel(guess that??) and they made all kinds of parts including bicycle as well as armour plating. They also performed pressure test on their tubes and the info exists in an iron & steel text from the turn of the 20th century. I guess Excelsior to have surfaced in the late 1890s or circa 1900 but a little more research might narrow the date. Now a set of tubes with Witten Excelsior and the trademark would be from the Witten area. Just the term "Witten", I'm not sure and it may have been a Cast Steel Works process manufactured in Liege.
Kind Regards,
Raimey
rse
