Perhaps the most interesting feature of this horn is the valve linkages. Many horns employ piston valves and many others employ lever activated rotary valves. This horn uses articulated levers to activate the piston valves as shown in the above photos. When the finger pallet is pressed (1) it pivots to raise the secondary lever (2) which in turn presses the valve piston (3). It works quite smoothly.

The only serial numbers on the horn are on the valve casings (right). The piston valve set is numbered 6412 on second valve casing and the rotary change valve is numbered 6413.  Both are also stamped with a five-pointed star and a circular wordmark with the following text:

DEPRINS FR
ANVERS
BORGERHOUT

In addition to identifying the maker, the very elegant label on the bell (see below,  right) states that the horn was awarded the Medialle d'Or at the Anvers, Belgium Exposition in 1930 and the Grand Prix at the Brussels Exposition in 1935.

The workshop was founded in 1901 in Borgerhout (Antwerp) by Petrus De Prins (b. Mechelen, Nov 28 1857;  d. Borgerhout - Mar 17, 1926).  His son Karel joined him in the business at a young age. De Prins was an Antwerp agent for Mahillon and Van Cauwelaert. A catalog for the Dutch market, around 1910, shows several horn and alto horn models (called "stellahoorns" and "waldhoorns"). The horn shown as model 86 is a Mahillon model 412.  Production was interrupted in 1914 for the duration of World War I. In 1918, production resumed in the workshop at the Lammekensstraat and the company was called  "Gebroeders De Prins" operated by the founder's sons Karel, Gustaaf, and Louis De Prins.

A Belgian catalogue of around WWII shows 3 main horn models, and some derived from other makers:
Nr. 101: Harmonie hoorn in mi b en fa gewoon model: 900 fr.
Nr. 102: Harmonie hoorn in mi b en fa model D.P. Artist: 925 fr.
Nr. 103: Harmonie hoorn in mi b en fa model D.P. virtuoso kan ook in Sib gemaakt worden:  1000 fr.
Nr. 104: Harmonie hoorn in mi b en fa of si b en fa, groote booring model D.P.  solist  1500 fr.
Nr. 105: radio wonder hoorn, model D.P., zeer groote booring, in si b en fa, mekanieke verlenging of verkorten der coulissen: 2500 fr
The model nr. 101 was a Mahillon 499 and nr. 102 a Van Cauwleaert Gantois.

The following information was provided by Decock Luc to the Cornet Connection website:
In 1901 father Petrus De Prinz took over a small existing business that cleaned musical instruments and made little repairs to them. Then from period 1903-1908 company notes talk about "De Prins, frères" (French). This is equivalent to "De Prins, Gebroeders" (Flemish/Dutch) or "De Prins, Brothers". Business was done by the 3 sons of the formerly mentioned Petrus : Karel, Gust, and Louis (First letters of names may form the 3 script letters).

During WWI (1914-1918) Gustaaf and Louis went to England and acquired more knowledge about manufacture of musical instruments. After WWI the production was restarted with the help of specialists from other factories. The activities were split amongst the 3 brothers :
Louis : responsible for brasswinds and percussion
Karel : responsible for woodwinds
Gustaaf : administration of the business

At the 1930 World Exposition in Antwerp a "Gold Medal" was received. At the 1935 World Exposition in Brussels a "Groote Prijs" (eq. Big Award) was received. Due to success the business increased and the company started to export instruments to the Philippines, Switzerland, Netherlands, Canada, Luxemburg, USA. Even a store was opened at Leopoldstad within former Belgian

With WWII (1940-1945) a difficult period started again. Musical activities dropped to zero. After the war another restart followed. At the end of the 40's the 3rd generation came into the business :
from 1947 :Herman, son of Karel
from 1951 : Raymond : son of Gustaaf

At the World Exposition of 1958 in Brussels the company presented the first clarinet made in superpolyamide material. But due to increasing international concurrence the business figures decreased.
1967 : Herman sold his part of the company to his cousin Raymond
1980 : Raymond died
1987 : Herman came back into the business; the company was led by his son Bruno.

Silently the company faded away... only a small "museum of wind instrument manufacture" remains today. It can be visited on request.