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 starts again with Poppaea as the motive behind the murder. Nero designed a ship that would open at the bottom while at sea. Agrippina was put aboard and after the bottom of the ship opened up, she fell into the water. Agrippina swam to shore so Nero sent an assassin to kill her. Nero then claimed Agrippina plotted to kill him and committed suicide. Her reputed last words, uttered as the assassin was about to strike, were "Smite my womb", the implication here being she wished to be destroyed first in that part of her body that had given birth