The Levin brothers were childhood acquaintances of Twain. They lived in Hannibal. They were nicknamed "Twenty-two." Henry Nash Smith argues that they may have been the basis of the name "Forty-four" in "Schoolhouse Hill" and "44" in "No. 44, The Mysterious Stranger." See William M. Gibson's note to 184.33 in the California edition of *The Mysterious Stranger.*