Norway has agreed to hand back thousands of skulls, stone figures, axes and other artefacts taken from Chile's Easter Island by the renowned Norwegian explorer Thor Heyerdahl.
The gesture will increase the pressure on London's British Museum to hand over its own 'moai' statue from Easter Island.
"This was what my father wanted," Thor Heyerdahl Jr told Norway's state broadcaster NRK after signing a deal to hand over the artefacts at a song-filled ceremony at the National Library of Santiago.
"This was extremely emotional for me, an absolute joy, and my father would probably have said exactly the same about the objects being given back."
Heyerdahl brought the artefacts to Norway in 1956, hoping to use them to prove his now discredited theory that the island's inhabitants had sailed across the Pacific from South America.
At the time he was at height of his fame, after turning his 6,000 mile voyage from Peru to French Polynesia on the balsa wood raft Kon-Tiki into a bestselling book and Oscar-winning documentary film.
According to his son, Heyerdahl pledged to return the objects once they had been analysed. But for the last 63 years, they have been on display at Oslo's Kon-Tiki Museum.
The museum's director Martin Biehl was quoted by the AFP news agency as saying that "our common interest is that the objects are returned and, above all, delivered to a well-equipped museum", adding that the process would "take time".
Tarita Alarcón Rapu, Easter Island's governor, said that the signing was "an emotional moment" for the indigenous Rapa Nui people.
"This means that our ancestors return to where they belong," she said.
The purpose of the Moai, the imposing basalt statues with oversized heads for which Easter Island is famed, remains a mystery. But many descendants of the indigenous Rapa Nui people believe they embody the spirits of prominent ancestors.
The signing ceremony took place during a state visit to Chile from Norway's King Harald V and Queen Sonja.
In August last year the mayor of Easter Island, Pedro Edmunds, wrote a letter to the British Museum calling for the return of Hoa Hakananai, usually translated as "stolen friend".
The imposing basalt statue was taken from Easter Island by a British naval captain in 1869 as a gift for Queen Victoria.
The British Museum has held discussions with officials from the island and the Chilean government, but so far has only expressed willingness to consider a loan of the statue.