In view of all this it is not difficult to understand why the man who for many years had done everything for himself, who had never wished to have either counselors or confidants about him, now that he was growing old needed the support of younger energies and of stronger wills.  But in his family he could rely only upon his son Drusus, who had now become a serious and trustworthy man, and in the year 22 A.D. he asked the senate that it concede to his son the tribunician power; that is, that they make him his colleague.  But the son did not suffice, and Sejanus therefore succeeded in making himself, together with Drusus, in fact, if not in name, the first and most active and influential collaborator and counselor of Tiberius.  He was even more active and influential than Drusus, for the latter was frequently absent on distant military missions to the confines of the empire, while Sejanus, as commander of the pretorian guard, was virtually always at Rome, where the emperor now appeared less and less frequently.

Such was the origin of the anomalous power of this man, who was not even a senator—­a power which was the result of the weakness of Tiberius and of the fierce discords which divided the aristocracy; and it was a power which must of necessity prove disastrous, especially to the party of Agrippina and Germanicus.  Although indications are not lacking that there was no great harmony or friendship between Sejanus and Drusus, it is evident that Sejanus, as the energetic representative of the interests of Tiberius, must have directed all his efforts against the friends of Agrippina, who was arousing the fiercest opposition to the emperor.  But in the year 23, an unforeseen event seemed suddenly to change the situation and to render possible a reconciliation between Tiberius and the party of Agrippina.  In this year, Drusus also, like so many other members of his family, died prematurely, at the age of thirty-eight, and on this occasion, for the time being, at least, no one raised the cry of poisoning.  This unexpected misfortune moved Tiberius profoundly, for he dearly loved his son, and it seemed for a moment to determine the triumph of Agrippina’s party.  Now that his son had been taken from him, where, if not among the sons of Germanicus and Agrippina, could Tiberius look for a successor?  And, as a further proof that Tiberius desired as far as possible to avoid conflict in the bosom of his family, he did not hesitate a moment, despite all the annoyances and difficulties which he had suffered at the hands of Agrippina and her friends.  He officially recognized that in the sons of Germanicus were henceforth placed the future hopes of his family and of the empire.  Of the two elder, Nero was now sixteen and Drusus was somewhat younger, though we do not know his exact age.  These he summoned to appear before the senate, and he presented them to the assembly with a noble discourse the substance of which Tacitus has preserved for us, exhorting the youths and the senate to fulfil their respective duties for the greatness and the prosperity of the republic.