When Baltic Sea divers first saw the wreckage through sonar, they thought it was a fishing boat.
But when they went to investigate, they discovered a 19th-century sailing ship “laden with” champagne, wine, mineral water and china.
They counted more than 100 bottles of champagne in a shipwreck off the Swedish coast.
Now Tomasz Stachura of Polish diving group Baltitech believes the shipment may have been destined for the Russian czar.
Baltic, which specializes in exploring Baltic shipwrecks, described the discovery as a “treasure”.
Mr Staczula, the team leader, said: “I have been a diver for 40 years. Every now and then you see a bottle or two.
“But I’ve never seen a crate like this with a wine bottle and a basket of water.”
The discovery is about 20 nautical miles (37 kilometers) south of the Swedish island of Ă–land.
Two divers said they were going for a “quick dive” but then disappeared for nearly two hours.
“So we already know there’s something very interesting at the bottom,” Mr Staciura added.
The clay water bottles were stamped with the brand name of the German company Selters, helping them date the wreck to 1850 to 1867.
Staczula said that while many people today are more interested in champagne, mineral water is a unique product that is “treated almost like a medicine” and “only found its way to royal tables.”
“It was so valuable that transport was accompanied by a police escort.”
Mr Stachula told the BBC he believed the goods could have been destined for the table of Russian Tsar Nicholas I – who reportedly lost a ship in the area in 1852.
“That would explain why the ship had these cargoes – they were very unique,” he said.
“Typically when we find a shipwreck, the cargo is very cheap.”
He believed the ship was heading across the Baltic Sea to Stockholm or St. Petersburg – again consistent with the theory.
“The dive itself only takes about 20 minutes,” he said. “But it might be more interesting to delve deeper into the archives.
“In the future, maybe we will learn more about this wreck.”
As for champagne and the prestigious mineral water, Mr. Stachula believes both drinks are drinkable today.
For now, the treasure remains in situ, with underwater archaeologists called in to assist. Swedish authorities have been notified and must manage it before it surfaces.
“It’s been lying there for 170 years, so let’s let it lie there for another year,” Mr Staczula said.