Story highlights A family in Mississippi discovered a letter from Thomas Jefferson in a box of heirlooms in their attic

The 1815 message was written to their ancestor U.S. Ambassador to France William Crawford

Washington (CNN) Always check the abandoned boxes in your attic because you never know what you might find.

A family in Mississippi discovered a rare letter from founding father Thomas Jefferson in a box of heirlooms, written to their ancestor, U.S. Ambassador to France William Crawford.

The four-page letter from the former president shows his reaction to the end of the War of 1812, comparing it to the American revolution. He discusses the honor of American independence and rails against the British.

The Raab Collection, a Philadelphia dealer of historical documents, is selling the letter for $325,000 on behalf of the family.

"The historical importance of this letter blew my mind," Nathan Raab, the vice president of The Raab Collection, told CNN. "When you read it, you feel like you're sitting next to Thomas Jefferson, getting his unfiltered thoughts."

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