A Winston Churchill signed bet realised £17,000 ($24,511) in a March 18 sale at Dreweatts & Bloomsbury in London.
The document originates from a dinner party in Minneapolis on January 23, 1901, held at the home of industrialist James C Young.
Churchill and Young, along with other guests, spent a long, boozy evening together.
One of the main subjects of conversation was the fate of the British Empire after Queen Victoria, who had died the day before.
Young was adamant the empire would begin to crumble, while Churchill was equally confident it would remain strong.
As the night wore on, they made a bet. Each promised to pay the other £100 (the equivalent of around £11,000 today) if they were proved wrong.
The document reads: "Mr. James C. Young bets Mr. Winston Churchill - one hundred pounds even - that within ten years from this date the British Empire will be substantially reduced by loss in Australia, or Canada, or India equal to a quarter by population of one of these provinces…"
It's signed by both men and by the poet Richard Le Gallienne, who acted as witness.
Churchill was ultimately proven right. The empire actually grew in size during the early 20th century and did not start to decline until the end of the second world war.
We have an exceptional collection of Churchill correspondence for sale, click here to take a look.
Please sign up to our free newsletter to receive exciting news about autograph auctions.