For decades, parodies featuring ominous, mysterious cults have been a favorite gag in pop culture. These fraternal brothers are often depicted in some type of underground lair, dressed in extravagant ceremonial robes with their faces hidden in their hoods, seated around a long table brimming with Gothic chalices, skulls, and glittering dark treasure. Like all art, creativity is sparked by a source of inspiration, and the inspiration for scenes like those have for centuries come from conspiracy theories, which often have profound impact regardless of their veracity. Indeed, conspiracy theories are nothing new: when the Great Fire of Rome occurred in 64 CE, Suetonius and Cassius Dio, two of Nero's ancient biographers, were adamant that it was the emperor himself who set the fire (or ordered it set), and they are the originators of the myth that Nero played the lyre, danced around his palace, and sang "The Sack of Troy" while Rome burned outside his windows.

Perhaps it should also not be surprising that the themes found in contemporary conspiracy theories are often echoed in ancient conspiracy theories. While some people still insist that Lyndon B. Johnson was in on John F. Kennedy's assassination, it was speculated across the ancient world that the young Macedonian king, Alexander the Great, conspired to have his own father, Philip II of Macedon, assassinated. Likewise, the New Age beliefs that Mesoamerican ruins in Mexico were somehow tied to extraterrestrials find common cause with people who believe the ancient Indus Valley site at Mohenjo-daro was destroyed by a nuclear weapon. And through it all, the lack of surviving documentary evidence about much of antiquity has allowed for all of the unknowns to become highly speculative sources of debate. For example, did Caesar's men burn the Library of Alexandria in the 1st century BCE, or was it destroyed later, if at all?