Seius Strabo, who had been made one of the prefects of the prætorian cohorts by Augustus, had a son, who, having been adopted by one of the Ælian family, was named in the usual manner L. Ælius Sejanus. This young man, who was born at Vulsinii in Tuscany, was at first attached to the service of Caius Cæsar, after whose death he devoted himself to Tiberius; and such was his consummate art, that this wily prince, dark and mysterious to all others, was open and unreserved to him. Sejanus equalled his master in the power of concealing his thoughts and designs; he was daring and ambitious, and he possessed the requisite qualities for attaining the eminence to which he aspired; for though proud he could play the flatterer; he could and did assume a modest exterior, and he had vigilance and industry, and a body capable of enduring any fatigue.
[14-24 A.D.]
When Drusus was sent to quell the mutiny of the Pannonian legions, Sejanus, whom Tiberius had made colleague with his father Strabo in the command of the prætorians, accompanied him as his governor and director. Strabo was afterwards sent out to Egypt, and Sejanus was continued in the sole command of the guards; he then represented to Tiberius how much better it would be to have them collected into one camp instead of being dispersed through the city and towns, as they would be less liable to be corrupted, would be more orderly, and of greater efficiency if any insurrection should occur. A fortified camp was therefore formed for them near the Viminal Gate, and Sejanus then began to court the men, and he appointed those on whom he could rely to be tribunes and centurions. While thus securing the guards, he was equally assiduous to gain partisans in the senate, and honours and provinces only came to those who had acquired his favour by obsequiousness. In all these projects he was unwittingly aided by Tiberius, who used publicly to style him “the associate of his labours,” and even allowed his statues to be placed and worshipped in temples and theatres, and among the ensigns of the legions.
Sejanus had in fact formed the daring project of destroying Tiberius and his family, and seizing the supreme power. As besides Tiberius and Drusus, who had two sons, there were a brother and three sons of Germanicus living, he resolved, as the safer course, to remove them gradually by art and treachery. He began with Drusus, against whom he had a personal spite, as that violent youth had one time publicly given him a blow in the face. In order to effect his purpose, he seduced his wife Livia or Livilla, the sister of Germanicus; and then, by holding out to her the prospect of a share in the imperial power, he induced her to engage in the plan for the murder of her husband. Her physician Eudemus was also taken into the plot, but it was some time before the associates could finally determine what mode to adopt. At length a slow poison was fixed on, which was administered to Drusus by a eunuch named Lygdus, and he died apparently of disease (23). Tiberius, who while his son was lying dead, had entered the senate house and addressed the members with his usual composure, pronounced the funeral oration himself, and then turned to business for consolation.
So far all had succeeded with Sejanus, and death carried off the younger son of Drusus soon after his father; but Nero and Drusus, the two elder sons of Germanicus, were now growing up, and the chastity of their mother and the fidelity of those about them put poison out of the question. He therefore adopted another course; and taking advantage of the high spirit of Agrippina, and working on the jealousy of her which Augusta was known to entertain, he managed so that both she and Livia should labour to prejudice Tiberius against Agrippina by talking of the pride which she took in her progeny, and the ambitious designs which she entertained. At the same time he induced some of those about her to stimulate her haughty spirit by their treacherous language. He further proposed to deprive her of support by destroying those persons of influence who were attached to her family, or the memory of her husband. With this view he selected for his first victims C. Silius and Titius Sabinus, the friends of Germanicus, and Silius’ wife, Sosia Galla, to whom Agrippina was strongly attached, and who was therefore an object of dislike to Tiberius. Omitting however Sabinus for the present, he caused the consul Visellius Varro to accuse Silius of treason for having dissembled his knowledge of the designs of Sacrovir, having disgraced his victory by his avarice, and countenanced the acts of his wife. Having vainly asked for a delay till his accuser should go out of office, and seeing that Tiberius was determinedly hostile to him, Silius avoided a condemnation by a voluntary death. His wife was banished; a portion of his property was confiscated, but the remainder was left to his children.
[24-25 A.D.]