One of the world's oldest bottles of Cognac, given to a distillery worker instead of payment, could fetch GBP 160,000 at auction.
The spirit dates from 1762, when Catherine the Great became empress of Russia and before an insect infestation "wiped out" vineyards across mainland Europe.
It has been stored, complete with original label, in a family cellar for 140 years.
Sotheby's spirits specialist Jonny Fowle told the PA news agency that the 258-year-old Cognac should still taste good and will have "maintained its character".
The sellers have had the "prized possession" in the cellar of their family home, "untouched for generations".
Their ancestors adopted a son in the 19th century, who went to work in the Cognac region of France for 10 years, until 1880, before the phylloxera insect infestation "wiped out" vineyards across mainland Europe.
"He probably finished his time in Cognac when phylloxera hit," Mr Fowle said.
"He returned home to his family and in lieu of payment he had a huge cart full of bottles of Cognac", which was "quite normal" for the period.
The family "decided to keep three", including the bottle going under the hammer, which was "already very old at the time.
"They kept it for another 140 years in their family before deciding to sell."
The bottle is one of only three Gautier Cognac 1762 bottles to survive.
The two others – in the Gautier Museum, France, and sold at auction in New York in 2014 for around GBP 48,000 – are smaller.
The Cognac is still good to drink, Mr Fowle said.
The auctioned bottle was opened in 2014 "but I've not been lucky enough to taste it", he added. "By all accounts it was enjoyed."
The "condition of the bottle (going under the hammer) is really good. There's not been that much evaporation", he added.
"We can assume the alcohol level in it is pretty high and that would have acted as a preservative for hundreds of years. The liquid in the bottle would have maintained its character."
Asked if he was tempted to have a sniff, he said: "No! I might be out of a job."
Family distillery Maison Gautier had obtained a Royal Warrant to produce Cognac from King Louis XV just seven years before the bottle was produced.
Other items up for auction include a whisky expected to fetch GBP 100,000.
The Cognac will go under the hammer at Sotheby's online sale, open for bidding from May 14 to May 28, with all items expected to fetch a total GBP 1.1 million.