This reverse type commemorates the protection of Nero from the Pisonian Conspiracy. Events of the years 64-65 AD defined the subsequent reputation of Nero as a cruel and self-indulgent ruler.
In 64 AD, a large section of central Rome burned; Nero's reputed singing of the destruction of Troy during the fire led to the later association of him "fiddling" as the city burned. Within the charred remains of the city's center, Nero constructed the Domus Aurea, or Golden House, so named because of the gilded tiles on its exterior.
Nero's "excesses" resulted in a conspiracy to overthrow and replace him with Gaius Calpurnius Piso. Among the conspirators were many high-ranking members of Nero's court including Seneca the Younger, the poet Lucan, and Petronius, who called himself Nero's "arbiter of elegance." To Nero, the failure of a conspiracy made up of those so close to him could have been achieved only through divine intervention. As the king of the gods oversaw the security of the Roman state, Nero believed it was Jupiter the Guardian (Custos) who had saved him from harm.