The treasure was the property of Maximilian I, Elector of Bavaria, and was lost when the vessel sank in the River Inn in May 1648.
Several new expeditions have been launched this month to try to find it after newspaper articles about the sinking stoked fresh interest in it.
Cornelia Ostler is the woman perhaps best equipped to claim it – but she is not yet part of the scramble. Her father Reinhold was a professional treasure hunter who travelled the world living off his finds and the books he wrote about them.
But he died of cancer in 2010 with the royal treasure of Maximilian I still undiscovered.
It was loaded aboard carts in Munich as Bavaria was threatened by Swedish and French forces at the close of the 30 Years War and the ruler wanted to get the valuables to safety.
The treasure was transferred in 40 crates to several boats on the Inn at Wasserburg to be transported to an imperial residence in Austria. But somewhere near Mühldorf, one of the boats was lost after colliding with a bridge pier and capsizing.
History records that several of Maximilian’s men died – both in the accident and in diving down to the wreck in a bid to rescue the plates, cutlery, bowls, chalices and ornamental tableware sculptures were lost.
Over the years the odd piece has been hooked by a lucky angler – the last one in 1925 when two silver plates were hauled up – but the bulk of the treasure remains missing, perhaps carried down the centuries much farther from the point where it was lost.
“It is one of the most precious imperial treasures in Germany that has never been found,” said Miss Ostler who has a massive archive of treasure hunting in Germany bequeathed to her by her father.
Reinhold led a large expedition in 1984 which involved ten divers scouring huge tracts of the riverbed.
Apart from finding a Celtic sword and a few coins the mission was a failure.
Cornelia is optimistic that with modern devices the treasure will be found – although perhaps not by her.
She added: “It cannot remain there forever. It is probably covered with thick mud, lighter pieces washed much further away.”