She persuaded her half-imbecile husband, Claudius, to set aside his child, Britannicus, in favour of her own son, Nero. Before Nero had been two years on the throne, Britannicus was dead, poisoned by the young monster who had been put into his place. Agrippina had no hand in this crime. On the contrary, it struck her with dismay. As long as the lad was alive, she could hold his rights in terrorem  over the head of her son, and keep the unruly youth in subjection to herself. When he was dead, she felt, says the historian, that her main-stay was gone, and that, as he adds with sinister significance, this was but the first kindred blood that the young despot would shed.

The quarrel between the two soon grew furious. The mother tried to make a party for herself; the son stripped her of all the honours which had been bestowed upon her. The breach indeed was not open. They still met; there were the common displays of affection, the kiss given and received; but Agrippina would have stripped her son of the power he owed to her, if she could; and Nero was only waiting his opportunity to rid himself at once of her obligation and his danger.

Poison was first tried. Three times it was administered, and each time it failed. She had fortified herself, it is said, against its action by antidotes. The same story is told of more than one distinguished personage of antiquity; but I fancy this science does not know of the possibility of any such safe-guarding against deadly drugs. Whatever the cause, the poison failed, and Nero had recourse to another method. He invited his mother to his house on the Campanian coast, the Brighton of Rome, at the same time expressing his regret if there had been anything unfilial in his conduct. He met her as she landed—she came by sea—embraced her affectionately, and invited her to dine with him. A vessel, very handsomely equipped, was at hand. Would she embark, he asked, and go by water to his palace? She declined—for reasons we shall soon be able to understand—preferring to be conveyed by a litter along the shore. Nero was most courteous and affectionate. He gave his mother the seat of honour; he talked long with her on subjects grave and gay. When she bade him farewell for the night, he kissed her more warmly than usual, "so deep was his dissimulation," says Tacitus, "or perhaps," he adds, one can hardly think seriously, "even his savage heart was touched by the thought that he should not see his mother again. Anyhow, his victim's suspicions were thoroughly lulled. She accepted the offer which she had refused before, and embarked.

The night was calm and starlit—"heaven would have it so," says the historian, "that the crime might not escape detection!" Agrippina lay on cushions in the stern; a favourite freed-woman was with her, and a trusted attendant steered. Suddenly the canopy fell. It had been weighted with lead, and the steersman was killed by the blow. The two women escaped, saved by the lofty side of the sofa on which they lay. Then the signal was given to remove the bolts which kept the vessel together (it had been so constructed as to come to pieces when these were withdrawn), but the machinery did not work. Then the rowers tried to upset the ship by throwing their whole weight on to one side. But all were not in the secret. Some resisted the movement. The vessel was upset indeed, but this was done so gradually that the passengers were lowered into the water without being hurt. The freed-woman, thinking to get the speedier help, cried out "I am the Emperor's mother," and was immediately despatched by blows from boat-hooks and oars. Agrippina made no sign and swam to shore, escaping with but one blow on the shoulder.

Agrippina now knew perfectly well what had been intended, but her only hope of safety was in not seeming to know it. She sent a message to her son. "She had escaped," she said, "a terrible danger. Of course he would be very anxious about her, but he must not come to see her, for she wanted rest." The affectionate son was indeed anxious, but it was the escape, not the danger, that troubled him. He pictured to himself the furious woman, whose courage he well knew, appealing to the protection of the soldiers, or making her way into the streets and reproaching him with her wound, and with the death of her friends. Could Seneca and Burrhus, once his tutors, now his counsellors, help him? He sent for them and asked their advice. Seneca was a philosopher who has left the world some admirable morality; Burrhus was a rough, honest soldier. One would like to hear that they rebuked the murderer to his face. But civic courage had degenerated at Rome under a century of despotism. Tacitus even doubts whether they had not been privy to the attempt. Anyhow they stood silent. They knew that they could not dissuade the wretch from his purpose. Possibly they knew that either the mother or the son must perish. At last the philosopher turned to his soldier colleague, and asked him whether the troops could be trusted to do the deed. Burrhus replied that they could not: the memory of Germanicus lived among them, and they would not raise a hand against his daughter. Let those who had failed with their poison and their ship find some surer way.

The advice was taken. The freedman who had been Nero's agent in the matter hurried with a band of assassins to Agrippina's villa. The shore was crowded with a curious and anxious multitude. The news had spread that the Empress-mother had been in peril of her life, but now was safe; and friends and acquaintances hurried to congratulate her, torch in hand, for it was now the dead of night. They fled at the sight of the armed men. The freedman and his followers burst into the villa, and made their way to the dimly lighted chamber, where the unhappy woman sat with a single maid. "Do you leave me too?" she cried, as her solitary attendant rushed from the room. In another minute the deed was done. Years before she had been warned—so the story ran—that this be would her end. She had consulted the astrologers, and they had told her that her son would be Emperor, and would slay his mother. "Let him slay," she cried, "if only he reign."