The Theatre War, Cowberry War, Cranberry War or Lingonberry War, was a brief war between Denmark–Norway and Sweden, starting on 24 September 1788, formally lasting until 9 July 1789. Although the decision to launch the attack was taken in Denmark, the majority of the attacking soldiers were Norwegians from the Norwegian army.

The Norwegian Army is the land warfare service branch of the Norwegian Armed Forces. The Army is the oldest of the Norwegian service branches, established as a modern military organization under the command of the King of Norway in 1628. The Army participated in various continental wars during the 17th, 18th, and 19th centuries as well, both in Norway and abroad, especially in World War II (1939–1945). It constitutes part of the Norwegian military contribution as a charter member of the North Atlantic Treaty Organization (NATO) since 1949.