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 the emperor, which would have made him a member of the imperial family. While this did make his ambitions clear, his request was denied. The loss may have been huge for Sejanus had the dissensions in the imperial household not been deteriorating. Relations were so bad that Agrippina refused to eat at Tiberius' dinner parties for fear of being poisoned. She also asked Tiberius if she could be allowed to remarry, which he also refused. If either of them were allowed to remarry it would have threatened the line of succession that Tiberius was comfortable with. By refusing Sejanus' request,