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 Elder it ended when the Younger Drusus died of seemingly natural causes on 14 September AD 23. After the death of Tiberius' son, Agrippina wanted to advance the careers of her sons, who were all potential heirs for Tiberius. To achieve this, Agrippina presented the Great Cameo of France to Tiberius. It was a personalized gift that positioned the family of Germanicus around the emperor. The work was designed to convince Tiberius to choose her children as his heirs. It is likely she was the one who commissioned the Great Cameo of France. Ultimately, the death of Tiberius' son elevated her