O’Farrell’s novel is based in historical fact and the real-life alleged murder of Lucrezia di Medici by her husband, Alfonso d’Este, Duke of Ferrara, in 1561. The official reason given for Lucrezia’s death just a year after she joined him in Ferrara was sickness, ranging from consumption (tuberculosis) to putrid fever (typhus). However, O’Farrell anchors her novel in the rumor, publicized in British poet Robert Browning’s popular poem “My Last Duchess” (1842), that Lucrezia was murdered by her husband. Browning’s work is a dramatic monologue voiced by Alfonso Duke of Ferrara. Its subject matter aligns with the novel in portraying a curious duchess whose “looks went everywhere” and who bestows her favor indiscriminately on too many things and places because she is “too easily impressed” (Robert Browning, “My Last Duchess,” 1842). The poem also mentions the rare white mule that Alfonso bestows on Lucrezia in the novel. In terms of narrative voice, Browning’s dispassionate hero’s ironically understated speech reflects the cool, controlled aspect of O’Farrell’s rendering of Alfonso.