The severed head links the beginning and the end of the novel. It is that of Boniface de La Mole, Mathilde's ancestor, beheaded in 1574, whose legend she cherishes, and in the last chapter it is that of Julien Sorel, whom Mathilde kisses and buries with her own hands.
The omen comes early. In Chapter V of Book One, in the church at Verrières, Julien finds a newspaper clipping about the execution of a certain Louis Jenrel in Besançon, a name made of exactly the letters of Julien Sorel, and he remarks: "his name ends like mine." Soon after, the reflection of the red curtains makes the water in the font look like blood.
In Paris, Julien hears that the family's ancestor had his head cut off at the Place de Grève after a political intrigue, and that Queen Margaret of Navarre, his lover, carried the head away in her carriage and buried it herself. Mathilde dresses in black on the anniversary of the execution and measures men by their courage in the face of death. When Julien begins to draw from its sheath, against her, an old sword from the library, Mathilde feels herself transported to the age of Charles IX and Henry III.
At the end, Mathilde reenacts the legend. "The memory of Boniface de La Mole and of Queen Margaret" gives her the courage to open the cloak that wraps the body. She places Julien's head on a marble table and kisses it on the forehead, then carries it in her lap to the grotto and buries it. For Mathilde the head passes from family heirloom to yardstick and, finally, to object, and it shows her love as a role played out to the end.