Pyramids, castles, palaces: symbols of power and status have taken many forms down the ages, and for the Vikings what really counted was the longship.

This month Norwegian archaeologists hope to complete their excavation of a rare, buried longship at Gjellestad, an ancient site south-east of Oslo. It is the first such excavation in Norway for about a century.

Most of the ocean-going ship has rotted away over the centuries, but archaeologist Dr Knut Paasche believes the layout of the iron nails will still enable a replica to be built eventually.

Ground-penetrating radar (GPR) revealed it to be about 19m (62ft) long and 5m (16ft) wide – putting it on a par with the well-preserved Oseberg and Gokstad Viking ships on display in Oslo.

Those ships were found on the western side of the wide Oslo Fjord.

In the 9th Century the Vikings started using sails, but they still needed strong rowers too for their epic voyages.

In their longships they travelled all around the British Isles, raiding coastal communities, then settling and leaving a legacy of fine craftsmanship, as well as Norse words and names.

The Norse Vikings ventured to Iceland and some then settled in Greenland and Vinland in North America – what later became Newfoundland.

The Gjellestad warrior longship dates from the pre-Christian Viking period 750-850 AD, Mr Paasche of the Norwegian Institute for Cultural Heritage Research (Niku) told the BBC.

“We don’t yet know if this was a rowing or sailing ship. Others, like the Gokstad and Tune ships, combined rowing and sailing,” he said.

Study of the keel will be crucial and, he said, “the keel looks very different from the others, which is really exciting”.