Germanic Post Horns
Signal horns are well known in many ancient cultures and are
known to have been used in Roman times to announce the
arrival of the emperor's messengers.  The European tradition
of regular postal coaches was firmly established during and
after the 16th century.  By the late 18th century, the German
Post horn was standardized in this shape and pitched
somewhere near modern Bb.  The calls required just two or
three tones but the desire to become more musical resulted in a
longer tube pitched in F or Eb, often with a transposing finger
hole.  In the mid-range, this raises the pitch by a fourth or to
Bb (on the F instrument).  The combination of the F and Bb
harmonic series allows for a diatonic scale in that octave, giving
the postilion the ability to play many folk tunes along with the
simple calls.  My example pictured in the first three images to
the left, pitched in F with 4 1/2 turns in the tubing, is the form
found commonly throughout the 19th century.  Although no
maker's mark is present, it is a deluxe instrument being made
of German silver with gold brass trim.  I believe that the
mouthpiece is original to this instrument and plays quite well.  
The bell rim diameter is 4 9/16" and maximum length from bell
rim to mouthpiece receiver is 10".   I have been told that a
deluxe post horn such as this is probably from the 1860s and is
called a "Bavarian post horn of honour".  These were awarded
to postilions for service or playing abilities.  
An identical
instrument was appraised on Bavarian television's "Kunst und
Krempel", a series very much like the British and American
"Antiques Roadshow".  That instrument had belonged to the
postilion to Kaiser William I before 1885.  I invite you to
contact me if you have any additional
information that you
might be able to offer.

In the early 19th century, post horns were also made with as
many as five keys or with two or three valves as pictured in
the fourth and fifth photos on the left.  The example with
double piston valves is on display at the
Boston Museum of
Fine Arts and still has no tuning slide since is was probably not
intended to play in a group of musicians.  The second of these
is the form most commonly found today and is tunable in order
to play in bands and orchestras.  It is fingered with the right
hand, since the player would not be driving the coach while
playing.  Most often these are pitched in Bb, the same as a
cornet, but this example and others that I have seen are pitched
in C.  I have not learned for sure, but my speculation is that
these are intended for use in the parlor or church, playing along
with the piano, organ, choir etc.  It is normally accepted  belief
that the French cornet-a-pistons and thus all modern cornets
and trumpets grew from these origins.

The next three photos to the left are a Prussian post horn
attributed to the maker C.W. Moritz in Berlin about 1880,
from the collection of Tom Meacham.  There are several other
examples of this model of post horn known, including
one in
the
Boston Museum of Fine Arts.  This is a lucky thing, since
this one was found with the bell garland missing.  We know
from the other examples that the garland was always engraved
with "Ehren Posthorn für den Postillon" followed by the name
of the original owner to whom it was presented.  When
restored, the last line was left blank, since we will never know
that name.  The opposite side is engraved with the Prussian
eagle, indicating that it was sanctioned by the state for use in
the official duties of the postillon (German and French; in
English we generally use "postilion").  Herbert Heyde, the
leading expert on European brass instruments, reports that
these post horns remained the property of the state and were
on loan to the postilion.  The engraving on this horn was
reproduced very accurately by master engraver
Geoffroy
Gournet
.  This instrument is pitched in high pitch Eb and, like
a natural trumpet, is played in the third and fourth octave of its
natural overtone series.  With only two (Berliner) valves
(whole step and half step), it is not fully chromatic, but was
only expected to play traditional signals of the postal system
with the added ability to play folk tunes and simplified national
airs.  There is no provision for tuning either the open tones or
the valve loops, since it was never intended to play along with
any other instruments.  As it is, it is remarkably easy to play in
tune with itself.  The mouthpiece pictured is not original and is
most likely from a "Fürst Pless horn" as described below.  

An instrument that is commonly confused with the Germanic
post horn is the German hunting horn or jagdhorn.  These are
pitched in Bb, roughly the same shape and modern examples
are available with or without valves.  They are traditionally
wrapped in green leather and have a name plate with "Fürst
Pless" embossed.  This signifies the origins under the late 19th
century Prussian rein of Hans Heinrich XI, the Fürst von Pless
or Prince of the duchy of Pless in Upper Silesia, a region of
Poland today.  The principal difference from the post horn is
that they have a faster/larger taper and flare, ending in a bell
more like a flugelhorn than a cornet.  Although not historically
accurate, these are a common choice for performing the post
horn parts in the orchestra when called for by Mozart, Mahler
and others.  Another fun variation is the taschenjadghorn or
pocket hunting horn, still in Bb, it is coiled so tightly with a
much smaller bore, it will fit in your jacket or coat pocket.

Further confusion of the name "post horn" is also caused by
the use in England and the US to describe very different
soprano brass instruments.  The more common is the English
post horn, similar to the modern English coach horn, but
shorter and higher pitched, usually in Ab.  Presumably, this
was an outgrowth of the traditional copper coach horn, pitched
around E, that was used on English postal coaches and then
also used on coaches of the aristocracy for similar signal
purposes.  The modern English coach horn is longer yet,
pitched in C or Bb and often a "herald" trumpet is substituted
at race tracks in order to play tunes for the patrons for extra
tips.  

Until very recently, another use of the term was forgotten to
history.  In the US starting in the early 1840s, when valved
brass instruments were starting to become popular, small
German style trumpets were being imported and then made in
the US shops and were called post horns as well.  It is not
known how this tradition started, but we can guess that it may
have come from confusion in the terms being imported from
Europe and England along with players and instruments.  
When the bore size of these instruments was increased in order
to modernize the design, they were then called cornets, the
name that we still use today.  Some of these earlier instruments
are featured elsewhere on this site, including
Graves post horns
and a very early
Fiske cornet derived from the earlier design.
Click on images for larger views.