Antique German rotary valve trumpet made by Oskar Ullmann Instrumentmaker Leipzig

Hi

I found a Oskar Ullmann Instrumentmaker Leipzig (all this engraved on the trumpet)   rotary valve trumpet. It was in a wooden hand made case. There is a porcelain name tag in the case M. Schmann.From what I have found out Oskar was born in 1875 and died in 1947 when he and his shop was blown up during an allied bombing.He apprenticed under his father Gustav Erhard Ullmann. Then in 1903 went to work for the Penzel Co. He took over the Penzel Co. in 1907.In 1937 he supplied the military bands with instruments.The trumpet has been repaired many times (some not so good). I believe it has the original mouth piece (as it looks hand made). All the valves work and the trumpet plays (I'm not very good).  The box is something in itself. Dove tail joints and is angular in shape. I assume that he made this while working with his father before 1903 (since his name only) is on it, and not the Penzel name. I'm not sure if he change the Penzel co. name when he took over in 1907.

.Any help will be greatly appreciated.