Bb trumpet by Ferdinand van Cauwelaert
This trumpet may seem unusual and exotic to most trumpet players
today, but this was the standard form for trumpets in Belgium until
the middle of the 20th century.  The great trumpet teacher and
composer Theo Charlier, played a trumpet very similar to this and,
indeed, the better known Belgian maker, Mahillon, made a
"Charlier Model" trumpet for many years.  French makers such as
Besson and Courtois made similar trumpets in the last half of the
19th century but moved on to trumpets that were much the same
as our modern piston valve trumpets (Besson in the 1880s and
Courtois after 1900).  The genesis of this style trumpets appears to
be in the reduction in size of the earlier style piston valve trumpets
in G or F such as the
Brown & Sons F trumpet featured on this
site.  The size of the bore is somewhat smaller as is the flare of the
bell, resulting in a very bright timbre, more what we expect in high
Eb and other smaller trumpets today.  This is a very responsive
and easy to play trumpet with good intonation and I would find it
very satisfactory in a small ensemble.  The bore measures .416"
and the bell rim diameter is 4 9/16".  The length with mouthpipe
shank removed is 18 1/8".  The shank is a reproduction and the
mouthpiece is from a 19th century French Besson trumpet.  

"The New Langwill Index"  reports that Ferdinand van Cauwelaert
opened his brass instrument making shop in Brussels in 1846.  
Always a fairly small shop, it specialized in Belgian style valve
trombones, French horns and trumpets.  It continued in business
until after WWII.  I don't have any way of knowing the date of
manufacture of this trumpet, but I believe that it is no later than the
1920s and could be before 1900.