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.
Claudia Acte became emperor in 54 AD, after his great-uncle/stepfather died—apparently poisoned, in the belief of contemporary historians, by his niece/wife, Agrippina, Nero's mother. A year into Nero's reign, encouraged by Seneca the Younger and Burrus, and against Agrippina the Younger's wishes, Nero took Acte as his mistress. Seneca especially was concerned that his young student would not be satisfied with his wife, Octavia, and might indulge in risky sexual exploits. This made Acte appear a safe outlet and a source of separation from Agrippina. Seneca and Burrus were on uneasy terms with Agrippina and were nervous about her political influence and