Incest of unequal gravity: the "incestus iuris gentium," which was applied to both Romans and non-Romans in the Empire, and the "incestus iuris civilis," which concerned only Roman citizens. Therefore, for example, an Egyptian could marry an aunt, but a Roman could not. Despite the act of incest being unacceptable within the Roman Empire, Roman Emperor Caligula is rumored to have had sexual relationships with all three of his sisters (Julia Livilla, Drusilla, and Agrippina the Younger). Emperor Claudius, after executing his previous wife, married his brother's daughter Agrippina the Younger, and changed the law to allow an otherwise illegal union.
Agrippina the Younger called back from exile to be a tutor to Nero. Messalina considered Agrippina's son a threat to her son's position and sent assassins to strangle Lucius during his siesta. The assassins fled in terror when they saw a snake suddenly dart from beneath Lucius' pillow—but it was only a sloughed-off snake-skin in his bed, near his pillow. In 47, Crispus died, and at his funeral, the rumor spread around that Agrippina poisoned Crispus to gain his estate. After being widowed a second time, Agrippina was left very wealthy. Later that year at the Secular Games, at the performance of the