Percy Bysshe Shelley   (1792 - 1822) was the husband of novelist Mary Wollstonecraft Godwin and a lyric poet in his own right. He was also a political writer promoting human progress through revolutionary thinking. 
 
Percy was a son of Sir Timothy Shelley (1753 - 1844) and Elizabeth Pilfold. His father was a politician and heir to a Baronet. His mother was a member of the landed gentry. The Shelleys were not a particularly prominent family but could claim descent from the Fitzalans, Earls of Arundel. Percy was educated at home, his childhood largely uneventful and considered happy. In 1804 he entered Eton College where his peace of mind would end abruptly. His high-pitched voice was a source of amusement for schoolmates and made him a frequent target for hazing He entered Oxford in 1810. 
 
His literary career started in 1810 with "Zastrozzi" (a Gothic novel), "Original Poetry by Victor and Cazire" (a poetry collection co-written with his sister Elizabeth) and "Posthumous Fragments of Margaret Nicholson" (a collection of subversive, satirical poetry co-written with Thomas Jefferson Hogg). Already his atheistic worldview was evident in these works. 1811 saw the release of "St. Irvyne; or, The Rosicrucian" (his second Gothic novel) and more importantly "The Necessity of Atheism", a political pamphlet. He was expelled from Oxford along with Hogg. He was given the choice to be reinstated if he publicly rejected his arguments in the work. He refused to do so, having a falling-out with his father. In 2006, an extant copy of a though-lost work known as "Poetical Essay on the Existing State of Things" was discovered. It also dates from 1811 and expresses anti-monarchical and anti-war views. In the context of the Napoleonic Wars it could brand Shelley a traitor.  
 
On 28 August, 1811, Percy married his first wife, Harriet Westbrook. Their marriage would last about three years, during which Percy was absent from home. He was engaged in various political causes, including taking part in Irish nationalistic rallies. His pamphlets promoting that cause did not endear him to the British government. In 1814, While meeting philosopher William Godwin, one of his heroes, Shelley met and became more interested in Godwin's teenage daughters. He run away to Europe with with Mary and her half-sister Claire Clairmont, abandoning his pregnant wife in the process. The trio were back before the end of the year but settled in a household of their own. 
 
In 1815, Shelley completed "Alastor, or The Spirit of Solitude", one of his major works. He wrote "Hymn to Intellectual Beauty" (1816) while vacationing with Byron, soon followed by "Mont Blanc". But 1816 ended in tragedy. Fanny Imlay, half-sister of Mary, committed suicide in October and Harriet in December. Percy married Mary on 30 December, 1816. He considered having a better chance of claiming custody of his two children by Harriet while married. 
 
His custody trial ended in defeat. His atheism convinced the court to pass custody of his children to foster parents. The period 1816-1818 had Percy acting within the same literary cycle as Thomas Loce Peacock, Leigh Hunt and John Keats. He continued writing atheistic rhetoric though having trouble publishing it. He faced financial trouble and left Great Britain to avoid a debtor's prison. Traveling to Venice and meeting Byron again revitalized him. The result "Prometheus Unbound", featuring the Titan who undermined the tyranny of Zeus. 
 
During his stay in Italy, two of his children by Mary succumbed to illness while another was born. He tried to register another daughter as his, Elena Adelaide Shelley. Whether she was an illegitimate daughter or a mere foundling, Percy tried and failed to pass her as his legitimate daughter. Elena died in 1820. Percy Florence Shelley  would be the only child of Percy and Mary to survive them. While Mary was left depressed, Percy was not affected as much. He had a series of love affairs and his productivity only increased.  
 
By 1822, Percy was working in launching his own magazine, "The Liberal". He wanted to offer an alternative to such conservative publications as "Blackwood's Magazine" and "The Quarterly Review". It wasn't to be. On 8 July, 1822, Shelley was sailing with his private schooner along with two friends. A sudden storm sunk the ship and drowned all three of them. Some doubts of his cause of death have been expressed. He had survived two murder attempts prior to his death and theories of his accident being an arranged one surfaced almost immediately following his death.  Either way, his body washed ashore and later cremated.  
 
His works were popularized following his death through the efforts of Mary to get them republished and introduced to a wider audience. Victorian intellectuals enjoyed his short poems, such as Ozymandias, while largely ignoring his larger and polemic works. No reputable house would publish them. However pirated copies of this ignored work were widely distributed about among radical thinkers and revolutionaries throughout the 19th century. 20th century biographers have acknowledged his lasting political and philosophical influence.