What is this Antique Brass Instrument on display at the Musical Instrument Museum in Brussels, Belgium? - Music: Practice & Theory Stack Exchange

Does anyone know what type of instrument this is? It looks like some type of Euphonium, but obviously very different.

Museum of keyboard instruments hi-res stock photography and images - Alamy

Various musical instrument hi-res stock photography and images - Page 5 - Alamy

The Brussels Musical Instrument Museum has some of the rarest instruments from around the world in its collection

Types of Musical Instruments, History & Examples - Lesson

MIM MIM

Musical Instrument Museum - Brussels, Belgium

File:7 Bells - back, Musical Instrument Museum, Brussels.jpg - Wikimedia Commons

Explore a vast array of Instruments from music cultures from around the world in the Musical Instrument Museum (MIM) in Brussels, Belgium.

Musical Instrument Museum - Brussels, Belgium

Musical instrument museum brussels hi-res stock photography and images - Alamy

Visiting the Musical Instruments Museum in Brussels - Bright Nomad

✓ MIM-Musical Instrument Museum - Data, Photos & Plans - WikiArquitectura

Various musical instrument hi-res stock photography and images - Page 5 - Alamy