In the early 1340s, the painter Ambrogio Lorenzetti (ca. 1290–1348) accepted a commission to paint a series of frescoes illustrating Franciscan narrative scenes for the chapter house of San Francesco in Siena, Italy. In the scene that so intrigued me, The Martyrdom of the Franciscans, Ambrogio depicted the execution of six Franciscans, possibly at a Mongo…