Cosimo I de' Medici, Grand Duke of Tuscany
The poem is preceded by the epigraph "Ferrara:", indicating that the speaker is most likely Alfonso II d'Este, the fifth Duke of Ferrara (1533–1598), who, at the age of 25, married Lucrezia di Cosimo de' Medici, the 14-year-old daughter of Cosimo I de' Medici, Grand Duke of Tuscany, and Eleonora di Toledo.