AElius, a native of Vulturnum in Tuscany, who distinguished himself in the court of Tiberius. His father's name was Seius Strabo; a Roman knight, commander of the pretorian guards. His mother was descended from the Junian family. Sejanus first gained the favour of Caius Caesar, the grandson of Augustus, but afterwards he attached himself to the interest and the views of Tiberius, who then sat on the imperial throne. The emperor, who was naturally of a suspicious temper, was free and open with Sejanus, and while he distrusted others, he communicated his greatest secrets to this fawning favourite. Sejanus improved this confidence; and when he had found that he possessed the esteem of Tiberius, he next endeavoured to become the favourite of the soldiers, and the darling of the senate. As commander of the pretorian guards he was the second man in Rome, and in that important office he made use of insinuations and every mean artifice to make himself beloved and revered. His affability and condescension gained him the hearts of the common soldiers, and, by appointing his own favourites and adherents to places of trust and honour, all the officers and centurions of the army became devoted to his interest. The views of Sejanus in this were well known; yet, to advance with more success, he attempted to gain the affection of the senators. In this he met with no opposition. A man who has the disposal of places of honour and dignity, and who has the command of the public money, cannot but be the favourite of those who are in need of his assistance. It is even said, that Sejanus gained to his views all the wives of the senators, by a private and most sacred promise of marriage to each of them, whenever he had made himself independent and sovereign of Rome. Yet, however successful with the best and noblest families in the empire, Sejanus had to combat numbers in the house of the emperor; but these seeming obstacles were soon removed. All the children and grandchildren of Tiberius were sacrificed to the ambition of the favourite under various pretences; and Drusus the son of the emperor, by striking Sejanus, made his destruction sure and inevitable. Livia, the wife of Drusus, was gained by Sejanus; and, though the mother of many children, she was prevailed upon to afflict her adulterer in the murder of her husband, and she consented to marry him when Drusus was dead. No sooner was Drusus poisoned, than Sejanus openly declared his wish to marry Livia. This was strongly opposed by Tiberius; and the emperor, by recommending Germanicus to the senators for his successor, rendered Sejanus bold and determined. He was more urgent in his demands; and, when he could not gain the consent of the emperor, he persuaded him to retire to solitude from the noise of Rome and the troubles of the government. Tiberius, naturally fond of ease and luxury, yielded to his representations, and retired to Campania, leaving Sejanus at the head of the empire. This was highly gratifying to the favourite, but he was not without a master. Prudence and moderation might have made him what he wished to be; but having offended the emperor beyond forgiveness, he resolved to retrieve his loss, and by one vigorous effort to decide the fate of the empire. He called together his friends and followers; he paid court to such as seemed disaffected; he held forth rewards and promises; and, having increased the number of his partisans, formed a bold conspiracy, resolved by any means to seize the sovereign power.

A powerful league was formed with astonishing rapidity, and great numbers of all descriptions, senators as well as military men, entered into the plot. Among these, Satrius Secundus was the confidential friend and prime agent of the minister. Whatever was this man's motive, whether fear, or views of interest, or ingratitude (for no principle of honour can be imputed to him), he resolved to betray the secret to Tiberius. For this purpose he addressed himself to Antonia, the daughter of Anthony the triumvir, the widow of Drusus, and the mother of Germanicus. When this illustrious woman, who was honoured by the court and revered by the people, heard the particulars, she sent dispatches to the emperor by one of her slaves. Tiberius was astonished, but not dismayed. The danger pressed; his habitual flouness was out of season; the time called for vigour and decisive measures. He sent Macro to Rome, with a special commission to take upon him the command of the praetorian guards. He added full instructions for Sejanus. his conduct in all emergencies. Early in the morning on the 15th, before the kalends of November, a report was spread, that letters had arrived at Rome, in which the emperor signified his intention to associate Sejanus with himself in the tribunitian power. The senate was summoned to meet in the temple of Apollo, near the imperial palace. Sejanus attended without delay. A party of the praetorians followed him. Macro met him in the vestibule of the temple. He approached the minister with all demonstrations of profound respect, and taking him aside, "Be not surprised (he said) that you have no letter from the prince : it is his pleasure to declare you his colleague in the tribunitian power; but he thinks that a matter of so much importance should be communicated to the fathers by the voice of the consuls. I am going to deliver the emperor's orders." Sejanus, elated with joy, and flushed with his new dignity, entered the senate-house; Macro followed him. As soon as the consuls arrived, he delivered the letter from Tiberius, and immediately went forth to the praetorian guards. He informed them, that by order of the prince, a large donative was to be distributed among the soldiers. He added, that, by a new commission, he himself was appointed their commanding officer; and, if they followed him to the camp, they would there receive the promised bounty. The lure was not thrown out in vain: the praetorian guards quitted their station. Laco, who stood near at hand, immediately surrounded the senate-house with a body of the city cohorts.

The letter to the consuls was confused, obscure, and tedious, only glancing at Sejanus, till at last the language of invective left no room for doubt. Sejanus kept his seat like a man benumbed, senseless and stupid with astonishment. His friends, who a little before congratulated him on his new dignity, deserted him on every side. He was commanded by the consul to rise and follow him, and being loaded with irons, was conducted to prison. His downfall filled the city with exultation. The populace, who worshipped him in the hour of prosperity, rejoiced to see the sad catastrophe to which he was now reduced. They followed in crowds, rending the air with shouts, and pouring forth a torrent of abuse and scurrilous language. The prisoner endeavoured to hide his face; but the mob delighted to see remorse and shame and guilt and horror in every feature of his distracted countenance. They reviled him for his acts of cruelty; they laughed at his wild ambition; they tore down his images, and dashed his statues to pieces. He was doomed by Tiberius to suffer death on that very day; but, as he had a powerful faction in the senate, it was not thought advisable, for the mere formality of a regular condemnation, to hazard a debate. Private orders were given to Macro to dispatch him without delay; but the consul, seeing the dispositions of the people, and the calm neutrality of the praetorian guards, judged it best to re-assemble the fathers. They met in the temple of Concord. With one voice Sejanus was condemned to die, and the sentence was executed without delay. He was strangled in the prison. His body was dragged to the Gemoneia, and, after every species of insult from the populace, at the end of three days was thrown into the Tiber. Such was the tragic end of that ambitious favourite. He fell a terrible example to all, who, in any age or country, may hereafter endeavour by their vices to rise above their fellow-citizens.