In short, Claudius had been persuaded to divorce Messalina and to marry her to Silius.  The passage from Suetonius, if carefully interpreted, clearly tells us this.  What means were employed to persuade Claudius to consent to this new marriage we do not know.  Suetonius refers to this, but he is not clear.  In any case, this point is less important than that other question:  Why was Messalina, after seven years of empire, willing to divorce Claudius and marry Silius?  The problem is not an easy one, but after long examination I have decided to accept with slight modification the explanation given by Umberto Silvagni in his beautiful work, “The Empire and the Women of the Caesars,” a book which contains many original ideas and much acute observation.

[Illustration:  The philosopher Seneca.]

Silvagni, who is an excellent student of Roman history, has well brought out how Silius belonged to a family of the aristocracy famous for its devotion to the party of Germanicus and Agrippina.  His father, who had been a great friend of Germanicus, had been one of the victims of Sejanus, and accused in the time of Tiberius under the law of high treason, he had committed suicide.  His mother, Sosia Galla, had been condemned to exile on account of her devotion to Agrippina.  Starting out with these considerations, and examining acutely the accounts of all the ancient historians, Silvagni concluded that behind this marriage there lay a conspiracy to ruin Claudius and to put Caius Silius in his place.  Messalina must sooner or later have felt that the situation was an impossible one, that Claudius was not a sufficiently strong or energetic emperor to be able to impose the disorganized government of himself and his freedmen upon the empire, and that any day he might fall a prey to a plot or an assassination.  What would happen, she must have asked herself, if Claudius, like Caligula, should some day be despatched by a conspiracy?  The same fate would doubtless be waiting for her, for, having killed him, the conspirators would certainly murder her also.  Consequently she entertained the idea of ruining the emperor herself in order to contribute to the elevation of his successor, and thus to preserve at his side the position which she had occupied in the court of Claudius.  But once Claudius had been slain, there would be no other member of the family of Augustus old enough to govern.  She therefore decided to choose him in a family famous for its devotion to Germanicus and the more popular branch of the house, thus hoping the more easily to win over the legions and the pretorians to the cause of the new emperor, Since the descendants of Drusus were dead, what other option remained to her than to choose a successor in the families of the aristocracy who had shown for them the greatest devotion and love?