The famous sculpture "Laocoön and His Sons" is featured prominently in several scenes, not merely as a backdrop but indeed as an object with which the Pope interacts. The ancient statue was unearthed only in 1506, more than a decade after the events depicted.
Juan confides Lucrezia that he had his wife murdered for abandoning him. In real life, Juan's wife Maria Enriques outlived her husband for about 40 years.