Tennent, Sir James Emerson (1804–69), politician, author, and traveller, was born in North St., Belfast, on 7 April 1804, third and only surviving son of William Emerson (d. 1821), of Ardmore, Co. Armagh, a successful Belfast tobacco merchant, and Sarah Emerson, youngest daughter of William Arbuthnot of Rockvale, Co. Down. Educated at the RBAI, he entered TCD in 1821, but left without taking a degree. It is thought that while travelling in Greece (among other countries) in 1824 he met Lord Byron, a fellow champion of Greek independence; receiving a commission from the Greek committee, he served as an artillery lieutenant. He recorded his observations of the country in A picture of Greece in 1825 (1826) and Letters from the Aegean (1829), a collection of articles originally published in Coburg's New Monthly Magazine. These were followed by The history of modern Greece, from its conquest by the Romans B.C. 146 to the present time (1830). One of the first elected members of the Belfast Natural History and Philosophical Society, he donated to its museum various items collected on his travels. He contributed to the Northern Whig and other journals. Though he was called to the bar at Lincoln's Inn (1831) it seems that he never practised.
He married (1831) Letitia Tennent, the only legitimate child of William Tennent (qv) of Temple House, Co. Fermanagh, a wealthy Belfast banker and liberal; they had two daughters and one son. After his father-in-law's death in 1832, he assumed his name and arms by royal licence, and succeeded to his extensive lands and fortune. Identifying himself as a liberal and reformer (and suspected of pro-repeal sympathies), he was elected MP for Belfast (1832–41, 1842–5) as a supporter of the whig administration. In 1834 he followed his political mentor Edward Stanley (qv) (later 14th earl of Derby) into the ‘Derby dilly’ grouping, which broke with the government over secularisation of certain Church of Ireland revenues, and eventually aligned with the conservatives. He opposed both repeal of the union and the demands of the Tenant League, while professing to support a just settlement of the land question. He energetically promoted the bill regarding copyright of designs for printed fabrics, publishing a treatise on the subject (1841); on its passage the following year, Manchester merchants presented him in appreciation with a set of plates valued at £3,000. Narrowly defeated in the August 1837 election, he was seated on petition in March 1838. In the July 1841 general election he was elected, but subsequently unseated on petition and a new writ issued; he regained the seat in the ensuing by-election (August 1842).
Secretary to the Board of Control for India (1841–3) under the tory government of Robert Peel (qv), Tennent resigned his parliamentary seat to serve as colonial secretary of Ceylon (latterly Sri Lanka) (1845–50), and was knighted on his appointment. Resented as an outsider by the colony's political establishment, he further alienated opinion by his administrative ineptness. His tenure was marked by severe suppression of the 1848 Kandyan uprising, trenchantly denounced by liberal British opinion, and resulting in his controversial testimony before a parliamentary inquiry. His treatise on Christianity in Ceylon (1850), a perceptive survey of successive missionary projects, included an historical sketch of what he termed ‘the Brahminical and Buddhist superstitions’; the treatment of Buddhism was, however, a notably tolerant assessment from the perspective of Victorian Christian belief. Gazetted to the governorship of St Helena, but prevented by illness from taking up the appointment, he re-entered parliament in an uncontested by-election as Tory member for Lisburn (January–December 1852), and was appointed secretary to the poor law board under Derby's government. Returned to his seat unopposed in the July general election, he resigned to become secretary to the Board of Trade (1852–67). His sympathy in this office with the manufacturing and merchant classes was reflected in his stance on commercial taxes.
Tennent's capacities as an administrator were dubious; Benjamin Disraeli's judgment of 1866, though harsh, was not unrepresentative: ‘the most inefficient and useless of our public servants . . . his de[partmen]t in a disgraceful state and himself a mere club gossip and office lounger’ (quoted in Silva, 23). His reputation rests on the landmark two-volume study Ceylon: an account of the island, physical, historical, and topographical (1859); an instant success, it went through five editions in its first eight months. Gracefully written and richly documented, ranging from analyses of the island's ancient irrigation civilisation and its modern coffee economy, to descriptions of its architectural heritage and social customs, the book remained a standard reference work well into the twentieth century. A section republished as Sketches of the natural history of Ceylon (1861) included Tennent's pioneering account of elephant behaviour. With his wide range of interests, he also published books on Belgium (1841), Wine: its use and taxation (1855), and The story of the guns (1864). Conferred with honorary degrees of LLD by TCD (1861) and Cambridge (1862), he was elected a fellow of the Royal Society (1862). Made a baronet on his retirement (1867), he passed the title to his son, Sir William Emerson Tennent (1835–76), with whom it expired. He died suddenly from a stroke in London on 6 March 1869, and was buried in Kensal Green cemetery. Charles Dickens, who had dedicated Our mutual friend (1864–5) to him, attended the funeral. A portrait bust by Belfast-born sculptor Patrick MacDowell (1799–1870) is in Belfast city hall.