European signal horns take several forms. The hunting horn, consisting of a large circular air-tube of brass, was worn hooked around the shoulder. Since they were portable, they were playable on horseback, or even while running. These horns only play one or two pitches; signals were differentiated by rhythm. Hunters had different calls to signal the start of the hunt, to call the hounds and attendants to order, to broadcast a kill, and others. It is the circular hunting horn that in the second half of the seventeenth century gradually was transformed into a concert instrument, with the addition of keys. This is the horn we know today as the French horn.
A smaller example of a European signal horn is the post horn. Like the hunting horn, it consists of a single coil of brass, but the coil is usually only a few inches across. It is called a post horn because it was played by people delivering the mail on horse-drawn coaches that would travel from town to town. They would blow it to signal the arrival and departure of the mail coach. The close identification this instrument had with the mail can be seen in the fact that many European countries, even today, have a post horn as the symbol for the mail service. A similar horn, though straight rather than coiled, was used on the London to Oxford mail until 1914.
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