Sienkiewicz alludes to several historical events and merges them in his novel, but some of them are of doubtful authenticity.
- In AD 57, Pomponia was indeed charged with practising a "foreign superstition", usually understood to mean conversion to Christianity. Nevertheless, the religion itself is not clearly identified. According to ancient Roman tradition she was tried in a family court by her own husband Aulus (the pater familias), to be subsequently acquitted. However, inscriptions in the catacombs of Saint Callistus in Rome suggest that members of Graecina's family were indeed Christians.
- The rumor that Vespasian fell asleep during a song sung by Nero is recorded by Suetonius in the Lives of the Twelve Caesars.
- The death of Claudia Augusta, sole child of Nero, in AD 63.
- The Great Fire of Rome in AD 64, which in the novel is started by orders of Nero. There is no hard evidence to support this, and fires were very common in Rome at the time. In Chapter 50, senior Jewish community leaders advise Nero to blame the fires on Christians; there is no historical record of this, either. The fire opens up space in the city for Nero's palatial complex, a massive villa with lush artificial landscapes and a 30-meter-tall sculpture of the emperor, as well as an ambitious urban planning program involving the creation of buildings decorated with ornate porticos and the widening of the streets (a redesign which is not implemented until after Nero's death).
- The suicide of Petronius is clearly based on the account of Tacitus.