This is based on the life of Lucrezia de Medici who lived in Florence in the 16th Century and was the subject of the famous Robert Browning poem My Last Duchess. At the age of 15 she was married off to the Duke of Ferrara who commissioned a marriage portrait of his new wife, inviting a renowned portrait artist to take on the job. Lucrezia though felt unwelcome in her new home where it was clear that her sole responsibility was to provide a son and heir and when that didn't happen, after less than a year, became increasingly certain that the Duke had plans to kill her. This is wonderful historical fiction.
