Query: Alto Horn vs Tenor

[MarChant]

With horns that old it is difficult with the names. Who named it and who misunderstood it? A hint may be found in old band music in the way parts are named. I think I saw Althorn in B in some 1900-1920 band arrangements, which of course remained unplayed like c-saxophone and octavin.
In the 19th century there was no clear nomenclature for the instruments and every maker tried to protect his invention by some patent so the next maker had to invent another feature AND another name for it.
When instruments are sold today by folks outside the musical knowledge the names get even more funny. I have heard the words "big trumpet" often enough when holding a tuba and with the comments on the ophicleide I could write a funny book!

In case of the Hüller, it is named "C- oder B-Althorn" in their catalogue (No. 1957), although I am not entirely sure as it could also be a "C- oder B-Bassflügelhorn" (No. 1971). I don't really see the difference from these pictures.