I suddenly found on Thomann these types of horns: Parforce horn and Fürst Pless Horn.
I searched for them on Wikipedia and similar sites, Google, etc., but all I find is in German or other languages. They are called like that in every country version of Thomann.
Since I could not find any information about these instruments, what are these instruments, what are they used for, how to play, what are they made of, etc.?
Parforce horn is a hunting horn in the German tradition. A brass instrument, a simplified French Horn.
Google will translate German information on the Internet into English.
"Parforce horns are primarily used in hunting for blowing hunting signals . The large curl allows you to put your head and arm through and carry the horn over your shoulder. This leaves both hands free for riding."
Fürst Pless Horn is a smaller type of hunting horn.
Again, Google Translate is your friend.
"The Fürst-Pless-Horn is still used as a signaling instrument for blowing certain hunting horn signals, the so-called hunting control signals, in company hunts. In addition, the instrument is also used in hunting customs and in concert in so-called brass corps, e.g. B. at Hubertus fairs , also with Parforce horns in B , are used."
