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 death on his conscience. He felt so guilty he would sometimes have nightmares about his mother. He even saw his mother's ghost and got Persian magicians to scare her away. Years before she died, Agrippina had visited astrologers to ask about her son's future. The astrologers had rather accurately predicted that her son would become emperor and would kill her. She replied, "Let him kill me, provided he becomes emperor," according to Tacitus. Agrippina the Younger Agrippina the Younger (Latin: "Julia Agrippina"; 6 November AD 15 – 23 March AD 59), also referred to as Agrippina Minor ("Minor", which is