Alfred Tennyson, 1st Baron Tennyson (6 August 1809 – 6 October 1892) was Poet Laureate of the United Kingdom after William Wordsworth and is one of the most popular English poets.
Much of his verse was based on classical or mythological themes, although In Memoriam was written to commemorate his best friend Arthur Hallam, a fellow poet and classmate at Trinity College, Cambridge who was engaged to Tennyson's sister but died from a cerebral hæmorrhage. One of Tennyson's most famous works is Idylls of the King (1885), a series of narrative poems based entirely on King Arthur and the Arthurian tales, as thematically suggested by Sir Thomas Malory's earlier tales on the legendary king. The work was dedicated to Prince Albert, the husband of Queen Victoria. During his career, Lord Tennyson attempted drama, but his plays enjoyed little success even in his lifetime.
Tennyson wrote a number of phrases that have become commonplaces of the English language, including: "nature, red in tooth and claw", "better to have loved and lost", "Theirs not to reason why,/Theirs but to do and die", and "My strength is as the strength of ten,/Because my heart is pure".
Alfred Tennyson was born in Somersby, Lincolnshire, a rector's son and one of 12 children. He is one of the descendants of King Edward III of England.  His father, George Clayton Tennyson, was the elder of two sons, but was disinherited at an early age by his own father, the landowner George Tennyson, in favour of his younger brother Charles, who later took the name Charles Tennyson d'Eyncourt. George Clayton Tennyson raised a large family but was perpetually short of money; he drank heavily and became mentally unstable. Tennyson and two of his elder brothers were writing poetry in their teens, and a collection of poems by all three was published locally when Alfred was only 17. One of those brothers, Charles Tennyson Turner later married Louisa Sellwood, the younger sister of Alfred's future wife; the other poet brother was Frederick Tennyson.
Tennyson attended King Edward VI Grammar School, Louth, and entered Trinity College, Cambridge in 1828, where he joined the secret society called the Cambridge Apostles. At Cambridge Tennyson met Arthur Henry Hallam, who became his best friend.
In 1829 he won a prize for one of his first pieces, on "Timbuctoo". 
In 1830 he published his first solo collection of poems, Poems Chiefly Lyrical (1830+). Claribel and Mariana, which later took their place among Tennyson's most celebrated poems, were included in this volume. Although decried by some critics as oversentimental, his verse soon proved popular and brought Tennyson to the attention of well- known writers of the day including Samuel Taylor Coleridge.
In the spring of 1831, Tennyson's father died, forcing him to leave Cambridge before taking his degree. He returned to the rectory, where he was permitted to live for another six years, and shared responsibility for his widowed mother and her large brood. His friend Hallam came to stay with him during the summer and became engaged to Tennyson's sister, Emilia Tennyson.
In 1833, Tennyson published his second book of poetry, which included his best-known poem, "The Lady of Shalott", a story of a princess who cannot look at the world except through a reflection in a mirror. As Sir Lancelot rides by the tower where she must stay, she looks at him, and the curse comes to term; she dies after she places herself in a small boat and floats down the river to Camelot, her name written on the boat's stern. The volume met heavy criticism, which so discouraged Tennyson that he did not publish again for 10 more years, although he continued to write.
In 1833, that same year,his friend Arthur Henry Hallam had a cerebral hemorrhage while on holiday in Vienna and died. It devastated Alfred, but inspired him to produce a myriad of poetry that has become some of the world's finest verse. However, roughly a decade of poetic silence followed Hallam's death.
Tennyson and his family were allowed to stay in the rectory for some time, but later moved to Essex. An unwise investment in an ecclesiastical wood-carving enterprise resulted in the loss of much of their money.
In 1842, while living modestly in London, Tennyson published two volumes of Poems, the first of which included works already published and the second of which was made up almost entirely of new poems. They met with immediate success. The Princess, which came out in 1847, was also popular.
It was in 1850 that Tennyson reached the pinnacle of his career, being appointed Poet Laureate in succession to William Wordsworth and in the same year producing his masterpiece, In Memoriam A.H.H., dedicated to Arthur Hallam. In the same year, Tennyson married Emily Sellwood, whom he had known since childhood, in the village of Shiplake. They had two sons, Hallam — named after his friend — and Lionel.
He held the position of Poet Laureate from 1850 until his death, turning out appropriate but mediocre verse, such as a poem of greeting to Alexandra of Denmark when she arrived in Britain to marry the future King Edward VII. In 1855, Tennyson produced one of his best known works, The Charge of the Light Brigade, a dramatic tribute to the British cavalrymen involved in an ill-advised charge on 25 October 1854, during the Crimean War. Other works written as Laureate include Ode on the Death of the Duke of Wellington and Ode Sung at the Opening of the International Exhibition.
Queen Victoria was an ardent admirer of Tennyson's work, and in 1884 created him Baron Tennyson, of Aldworth in the County of Berkshire and of Freshwater on the Isle of Wight. He was the first English writer raised to the Peerage. A passionate man with some peculiarities of nature, he was never particularly comfortable as a peer, and it is widely held that he took the peerage in order to secure a future for his son Hallam. Recordings exist of Lord Tennyson declaiming his own poetry, which were made by Thomas Edison, but they are of relatively poor quality.
Towards the end of his life Tennyson revealed that his "religious beliefs also defied convention, leaning towards agnosticism and pandeism":
Tennyson continued writing into his eighties, and died on 6 October 1892, aged 83. He was buried at Westminster Abbey. He was succeeded as 2nd Baron Tennyson by his son, Hallam, who produced an authorised biography of his father in 1897, and was later the second Governor-General of Australia.