Copper coins and a 70-year-old map with an "x" may lead to a discovery that could rewrite Australia's history.
Australian scientist Ian McIntosh, Professor of Anthropology at Indiana University in the United States, plans an expedition in July that has stirred the archaeological community.
The scientist wants to revisit the location where five coins were found in the Northern Territory in 1944 that have proven to be 1000 years old, opening up the possibility that seafarers from distant countries might have landed in Australia much earlier than believed.
In 1944 during World War II, after Japanese bombers had attacked Darwin two years earlier, the Wessel Islands - an uninhabited group of islands off Australia's north coast - had become a strategic position to help protect the mainland.
Aussie soldier Maurie Isenberg was stationed on one of the islands to man a radar station and spent his spare time fishing on the idyllic beaches. While sitting with his fishing-rod, he discovered five coins in the sand.
He didn't have a clue where they could have come from but pocketed them anyway and later placed them in a tin. In 1979 he rediscovered his "treasure" and decided to send the coins to a museum to get them identified. They proved to be 1000 years old.
Still not fully realising what treasure he held in his hands, he marked an old colleague's map with an "x " to remember where he had found them.
The coins raise many important questions: How did 1000-year-old coins end up on a remote beach on an island off the northern coast of Australia? Did explorers from distant lands arrive on Australian shores way before James Cook declared it "terra nullius" and claimed it for the British throne in 1770?
We do know already that Captain Cook wasn't the first white seafarer to step on Australia's shores. In 1606 a Dutch explorer named Willem Janszoon reached the Cape York Peninsula in Queensland, closely followed a few years late by another Dutch seafarer Dirk Hartog.
And the Spaniard Luiz Vaez de Torres discovered the strait between Papua New Guinea and Australia, which was later named Torres Strait in his honour.
McIntosh and his team of Australian and American historians, archaeologists, geomorphologists and Aboriginal rangers say that the five coins date back to the 900s to 1300s.
They are African coins from the former Kilwa sultanate, now a World Heritage ruin on an island off Tanzania. Kilwa was once a flourishing trade port with links to India in the 13th to 16th centuries.
The copper coins were the first coins ever produced in sub-Saharan Africa and, according to McIntosh, have only twice been found outside Africa: once in Oman and Isenberg's find in 1944.
Archaeologists have long suspected that there may have been early maritime trading routes that linked East Africa, Arabia, India and the Spice Islands even 1000 years ago. Or the coins could have washed ashore after a shipwreck.
McIntosh wants to answer some of these mysteries during his planned expedition to the Wessel Islands in July.