Leopold Uhlmann Flugelhorn in C
The flugelhorn (bugle) was one first instruments to have valves applied to it, and while exact origins may be unknown, it was certainly first popularized in the Germanic countries. Leopold Uhlmann was one of the most important makers in the early development of valved brass. He had been granted a patent for improvements in double piston valves in 1830 and is best known for his excellent "Vienna Horns", the model for those still in use today. He was making flugelhorns with double piston valves in those early years and with rotary valves similar to those shown here by 1843. Difficult to date accurately, this instrument may have been made after the death of the senior Leopold in 1879. It is a very high quality instrument in both design and construction and the extensive engraved decoration is further indication that it is not an average instrument.
I have encountered enough German and Austrian flugelhorns in the key of C to assume that there is a traditional use for them. I would assume that it is similar to American choral or parlor cornets in C and ballad horns an octave lower. These were intended for use by amateurs reading the music from the piano, organ or vocal arrangements and would also be useful for social orchestras with variable instrumentation. For comparison, the last photo below shows it standing next to a more generic 20th Century German flugelhorn in Bb.
I also want to comment on the lack of appreciation for rare and beautiful antique instruments such as this. I had this on my list of instruments for sale for several years before finding a happy buyer at a very low price.
Another very interesting instrument, featured on this website, made by Leopold Uhlmann for inventor and musician, C.H. Eisenbrandt, is the unique double cornet in Bb and Eb.