son of Claudius and Messalina, appears to have been born in the early part of the year A. D. 42, during the second consulship of his father, and was originally named Claudius Tiberius Germanicus. In consequence of victories, or pretended victories, in Britain, the senate bestowed on the emperor the title of which was shared by the infant prince and retained by him during the remainder of his life as his proper and distinguishing appellation. He was cherished as the heir apparent to the throne until the disgraceful termination of his mother's scandalous career (A. D. 48); but Claudius, soon after his marriage with the ambitious and unscrupulous Agrippina, was prevailed upon by her wiles and the intrigues of the freedman Pallas, her paramour, to adopt L. Domitius, her son by a former husband, to grant him Octavia, sister of Britannicus, in marriage, and to give him precedence over his own offspring. This preference was publicly manifested the year following (51), for young Nero was prematurely invested with the manly gown, and received various marks of favour, while Britannicus still wore the simple dress of a boy. Indications of jealousy were upon this occasion openly displayed by Britannicus towards his adopted brother, and Agrippina seized upon his conduct as a pretext for removing by banishment or death the most worthy of his preceptors, and substituting creatures of her own in their place. Claudius is said before his death to have given tokens of remorse for his conduct, and to have hastened his own fate by incautiously dropping some expressions which seemed to denote a change of purpose. After the accession of Nero, Britannicus might perhaps have been permitted to live on in harmless insignificance, had he not been employed as an instrument by Agrippina for working upon the fears of her rebellious son. For, when she found her wishes and commands alike disregarded, she threatened to bring the claims of the lawful heir before the soldiery and publicly to assert his rights. Nero, alarmed by these menaces, resolved at once to remove a rival who might prove so dangerous: poison was procured from Locusta--the same apparently whose infamy has been immortalized by Juvenal--and administered, but without success. A second dose of more potent efficacy was mixed with a draught of wine, and presented at a banquet, where, in accordance with the usage of those times, the children of the imperial family, together with other noble youths, were seated at a more frugal board apart from the other guests. Scarcely had the cup touched the lips of the ill-fated prince, when he fell back speechless and breathless. While some fled, and others remained gazing in dismay at the horrid spectacle, Nero calmly ordered him to be removed, remarking that he had from infancy been subject to fits, and would soon revive. The obsequies were hurried over the same night; historians concur in reporting, that a terrible storm burst forth as the funeral procession defiled through the forum towards the Campus Martius, and Dion adds, that the rain, descending in torrents, washed away from the face of the murdered boy the white paint with which it had been smeared, and revealed to the gaze of the populace the features swollen and blackened by the force of the deadly potion.

There is some doubt and confusion with regard to the date of the birth of Britannicus. The statement of Suetonius (Suet. Cl. 27), that he was born in the second consulship of Claudius and on the twentieth day of his reign, is inconsistent with itself; for Claudius became emperor on the 24th of January, A. D. 41, and did not enter upon his second consulship until the 1st of January, A. D. 42. Tacitus also has committed a blunder upon the point, for he tells us, in one place (Ann. 12.25), that Britannicus was two years younger than Nero; and we learn from another (Ann. 13.15), that he was murdered at the beginning of A. D. 55, a few days before he had completed his fourteenth year. But we can prove, from Tacitus himself (Ann. 12.58, 13.6), that Nero was born A. D. 37, and from Suetonius that the event took place upon the 15th of December; therefore, according to this last assertion, Britannicus must have been born in the year 39 or at the beginning of 40 at latest; but this would bring him to the completion of his fifteenth year in 55. If Britannicus was born on the twentieth day after his father's accession, then he would be on the eve of completing his fourteenth year in January, 55; if he was born in the second consulship of Claudius, and this seems to be the opinion of Dio Cassius (9.12), he was only about to enter upon his fourteenth year. Under the first supposition, he was somewhat more than three years younger than Nero; under the second, somewhat more than four. (Tac. Ann. 11.4, 26, 32, 12.2, 25, 41, 13.15, 16; Suet. Cl. 27, 43, Nero, 6, 7, 33; D. C. 9.12, 22, 34, Ixi. 7.)