To the backdrop of the vast Jelling stones, Denmark on Tuesday granted the inventors of Bluetooth technology permission to use the name and symbol of Harald the Bluetooth for the next 1,000 years.

"In a spirit of goodwill and cooperation, we hereby authorise you to continue to use the name, Harald Bluetooth, for the next 1,000 years," said a symbolic statement from the Jelling museum, which owns the eponymous runestones that tell the story of the king and his family.

King Harald I Blatand — Harald Bluetooth — was a key historical figure in 10th-century northern Europe, famous for his adoption of Christianity, turning his back on the cult of Odin and Thor.

The man who owes his nickname to a root canal, or according to other sources to his immoderate taste for blackberries and bilberries, was also the father of Norway's union with Denmark, which lasted until 1814.

Modern-day Bluetooth, which enables electronic equipment to connect without cables, owes its name to the unifying king.

"The idea behind the new technology was that it should connect and unify. Just like Harald Bluetooth did when he unified Denmark and Norway," explained one of the inventors of the technology, Jim Kardach, quoted in a statement.

"We sincerely regret not seeking your permission before borrowing the name… We acknowledge that it was a rather cheeky move on our part."