I bought a box of stuff (mostly junk) from a farmer in Wisconsin to resell in my antiques booth in SE Pennsylvania. Rolled up in a paper towel roll was a letter from President Grover Cleveland to Queen Victoria congratulating her on her 50th Jubilee(ascension to the crown). It was authenticated and valued at $7K. It’s hanging in my dining room.
Great story. My father died almost two years ago. He had a lot of stuff in his house, and I went through all of it. I found some interesting things too — nothing quite like what you found — but interesting to me. You never know what someone has left behind.