June 20, 1810

The circumstances of Fersen's death, exactly nineteen years after the Varennes debaucle, are complicated and I don't understand enough of Swedish history to relate them. I do know that the new King, Carl August, died while on horseback, probably of a stroke, but at the time, it was believed to have been by poison. Although they were later exonerated, Fersen and Sophie were accused of being involved in his death. As Fersen led the funeral procession, as was his responsibility as Grand Marshall of Sweden, the crowd got out of control and, sparing you a detailed description, killed Fersen. Because the military troops stood by and didn't prevent some believed that the government sanctioned the murder.

After his death, his devoted sister, Sophie, raised a monument on the grounds of one of the family's castles, which said, in Swedish, "To an unforgettable brother, the courage in his last moments on the 20th of June 1810, bears testimony to his virtues and clean conscience".