The funerary monument of Bona Sforza, Duchess of Bari and Queen of Poland, in the Basilica of San Nicola in Bari has been a subject of discussion since the uncovering, in 1918, of documents which assign the marble authorship to a team of minor sculptors working in Naples around 1589–1593. Whilst research has focused on the history of this sepulchre, the name of the architect whom the queen’s daughter and heir, Anna Jagiellon, commissioned to design the tomb has remained unknown. Zygmunt Waźbiński, in 1979, proposed to attribute the project to Tomasz Treter, a canon from the Basilica of Santa Maria in Trastevere in Rome; this attribution, however, can no longer be upheld. This essay reviews the history of Bona’s monument and reassesses the question of its authorship. New evidence sheds light on the tomb’s models and reconnects its design to late-sixteenth-century tomb sculpture in Naples.