Recipe for a historical mystery: 1) Find an unsolved mystery from a past time period. 2) Think up a plausible solution for the mystery, then take some historical characters and have them discover the truth. 3) Come up with a plausible explanation for why, if these people solved the mystery, it remains unsolved to this day.
Recipe for a historical literary mystery: repeat the steps above, shake vigorously, and add a dead writer of your…