A historical character, Sanborn is a member of the "Secret Six," a group of wealthy, influential abolitionists who secretly fund John Brown. Narrator Sir Harry Flashman first meets Brown in Sanborn's Concord, MA, home. Flashy describes him as "as intense and poetic as could be, with his fluffy whiskers and anxious eyes" (pg. 204). "Yes, indeed," is Sanborn's favorite phrase; saying it, he always rubs his hands. He babbles about Brown's health and the fatigue of traveling before running off to see if Brown is available to meet. Later, at a birthday celebration for Brown, Sanborn reads an ecstatic piece by Artemus Ward about Brown's speech in Cleveland, OH.