Blowing horns and Prillar horns (Cow and bark)
Blowing horns of varied sizes are commonly thought to have been sounded in battle. However true this is, the primary purpose was to inform a village of your arrival when travelling. Failure to do so may result in your being mistaken as an intruder, the consequence of which may have been deadly!
Prillar horns were also in use, possibly as a predominantly female instrument. These horns contain noted holes and are end blown (unlike the Gemshorn of the 15th century which had the large end blocked by wood with a fipple carved into it); the most likely use was for communication in poor weather. A four-holed instrument was found at Vasterby in Sweden.
A regular blowing horn is easy to sound, the Prillar horn by contrast is extremely difficult.
Played by Corwen Broch here:
Credit: James Hulme