A rare letter signed by three of the Founding Fathers of the United States is going on sale, and is expected to fetch up to $1 million when it goes under the hammer next week.

Bearing the signatures of John Adams, Benjamin Franklin and Thomas Jefferson, the letter is addressed to the “Envoy Extraordinary of the King of the Two Sicilies” and seeks negotiations for a treaty of amity and commerce, according to Bonhams, the auction house handling the sale.

“An important expression of the emerging American policy of free trade, likely the only available example of any letter signed by all three of these Founding Fathers, the men most responsible for the Declaration of Independence,” said Bonhams in a listing on its website.

Dating from 1784, the letter was written after America had achieved independence, but at a time when it wasn’t clear whether the new nation would succeed.

 The letter is an example of America's emerging foreign policy at the time. Mandatory Credit:Courtesy Bonhams via CNN Newsource
 

That year, Congress commissioned Adams, Franklin and Jefferson to establish treaties with 20 other nations, thereby strengthening America’s position in the world.

“These treaties of ‘Amity and Commerce’ authorized by Congress just after Independence, and well before the enactment of a Federal Constitution, were essentially the establishment of a new and heavily trade-based system that would remake the face of international politics,” adds Bonhams.

Bidding starts at $550,000, and the letter is expected to fetch up to $1 million when it goes under the hammer on November 12.

Objects and artifacts linked to the founding fathers often prove popular at auction, attracting astronomical bids.

In 2017, manuscripts, personal letters and hundreds of other documents from founding father Alexander Hamilton’s desk sold for a total of $2.6 million at Sotheby’s in New York, according to the auction house.

And history buffs will also be able to bid on other historic items, including a lock of George Washington’s hair, at a sale coordinated by New York-based Guernsey’s auction house on November 22.