Wikipedia
Flatbrød (literally "flat-bread") is a traditional Norwegian unleavened bread which is currently usually eaten with fish, salted meats and soups. Originally it was the staple food of Norwegian shepherds, peasants, and Vikings.
The basic ingredients are barley flour, salt, and water, though many varieties exist which incorporate other staples.
It was once generally eaten in all meals, most often with cured herring and cold boiled potato, often along with sour cream and/or butter. Another use is served with betasuppe, a traditional meat soup. The thinner the bread is, the better it is. It is rolled and then cooked on a large griddle. The tradition of making flat bread used to be passed down through generation after generation by housewives. And each person had their own recipe for preparing it. It's still an important part of Norwegian food traditions, but it is now almost only made on a commercial basis. Flat bread is dry and free from water so it is possible to store it for a long period of time