==Babası Claudius'un ölümü ==
The actions Claudius took to preserve his rule in the short-term were not easily undone as Britannicus approached manhood. In late 54, Britannicus was within 6 months of reaching manhood by Roman tradition, and had matured early. According to the historian [[Suetonius]], Claudius began to mention divorcing Agrippina and dismissing Nero now that he was no longer needed. In preparation, Claudius commended both his son and adopted son to the Senate as equals in his last Senate address. Suetonius reports that Claudius now admonished his son to grow up quickly, implying that everything would be righted when he assumed the [[toga virilis]].
Sadly for Britannicus, Nero's supporters acted to prevent this. On [[October 13]], [], Claudius died, perhaps by natural causes or perhaps murdered by Agrippina. Tacitus claims that Britannicus and his sisters were locked in their rooms to ensure that no counter claim could be made to Nero's succession. Nero spoke the elegy at the emperor's funeral and took sole power. Claudius' new will, which either granted joint-rule to Britannicus and Nero or just Britannicus, was suppressed by the new emperor's men in the senate<ref>Barrett argues that Tacitus reference to the will being suppressed so as to prevent outrage about Nero meant that the will did not name Nero as primary or sole heir. Therefore the Senate's elevation of Nero would cause outrage if the will were read</ref>. The freedman [[Tiberius Claudius Narcissus|Narcissus]], Britannicus' champion according to Tacitus, was quickly put to death. Britannicus was pushed to the background.
Britannicus survived for a few months under the rule of his adopted brother, mostly ignored, but the doings of his step-mother Agrippina led to his death. In early 55, one of Agrippina's favorites, the freedman [[Pallas (freedman)|Pallas]], was sacked from his job as secretary of the treasury - a post he had held since the reign of Claudius. According to Tacitus, Agrippina reacted violently to this slight by Nero. She declared that she repented of her actions to bring Nero to the throne, and would throw in her lot with Britannicus, the true heir who would soon come of age. She threatened to take the boy to the Praetorian camp, where she would admit to murdering Claudius and Britannicus would be declared emperor. Nero did not take this threat lightly.
Tacitus recounts Nero's numerous attempts to publicly undermine Britannicus' image. One such attempt was when Nero asked Britannicus to sing at a drunken party, months before his 14th birthday. Britannicus however, not only avoided humiliation, but also generated sympathy amongst the guests, after singing a poem telling the tale of how he had been cast aside in favour of Nero. Tacitus also stated that a few days before his death, Britannicus was sexually molested by Nero.
According to Tacitus, Nero moved against Britannicus, employing the same poisoner, [[Locusta]], who had been hired to murder his father, Claudius. The first dose failed, and Nero decided to throw caution in the wind. Britannicus was poisoned at a dinner party attended by his sister, [[Claudia Octavia]], Agrippina, and several other notables. The assassin avoided being given away by a food taster by adding the poison to his drink when Britannicus asked for it to be cooled, as he felt it was too hot. The substance was instantly fatal, and Britannicus fell to the floor foaming at the mouth. He died on [[February 11]], [], one day before his 14th birthday, less than a month before he was to assume manhood, and just four months after his father's death<ref> According to Barrett. Most authors agree he died in that month</ref>. Nero dismissed the murder by claiming that the boy suffered from epilepsy. Some modern historians, particularly Anthony Barrett, suggest that he may have indeed suffered from the disease, and that a particularly bad seizure killed him. This may also be the reason for his eclipse by Nero - although Claudius never spurned his son on purpose. Britannicus was quickly buried in the [[Mausoleum of Augustus]], the last of the Julio-Claudians to be interred there.
According to [[Suetonius]], Britannicus was good friends with the future Emperor [[Titus]], whose father [[Vespasian]] had commanded legions in Britain. As part of the Flavian's attempts to link themselves with the Julio-Claudians, Titus claimed that he had been seated with Britannicus on the night he was killed. He even claimed to have tasted the poison, which resulted in a serious and long illness. Titus would go on to erect a gold statue of his friend, and issue coins in his memory.