Viking house in ring fortress. Cutaway artwork of the inside of a Viking longhouse in one of the circular Viking fortresses known as trelleborgs. The remains of these forts and buildings have been found in what is now Denmark and Sweden, dating from the Viking Age (8th to 11th centuries). The fortress wall and longhouse are constructed from wood, raised on stone foundations. The longhouse has a thatched roof. The inside is a single large communal area, with a central cooking fire and a section for livestock. Furs and rugs are on benches and the walls, along with shields, weapons and animal head trophies.