Conyngham, Henry (1766–1832), 1st Marquess Conyngham , landlord and courtier, was born 26 December 1766, the elder twin son of Francis Pierpoint Burton (qv), 2nd Baron Conyngham, and his wife Elizabeth, daughter of Nathaniel Clements (qv). He succeeded his father (who took the name Conyngham on succeeding to the title in 1781) as third Baron Conyngham in 1787, and was created Viscount Conyngham in 1789. On 5 July 1794 he married Elizabeth Denison (1769–1861), daughter of the wealthy English banker Joseph Denison; they had five children (three boys and two girls). On the death of his uncle William Burton Conyngham (qv) in 1796, Henry inherited his Donegal and Meath estates, re-uniting them with the Clare and Kent family holdings that had been divided between his father and uncle on the death of his great uncle Henry Conyngham (qv) (1705–81), 1st Baron and Earl Conyngham.
As a magistrate, Henry Conyngham took a hard line against political and agrarian protest in the 1790s and was appointed captain of the Slane Yeomen Cavalry in October 1796; he was created Viscount Mountcharles and Earl Conyngham in 1797. A good parliamentary speaker and a firm ally of the government in the Irish house of lords, he strongly supported the act of union and after its passing in 1801 was elected one of the twenty original representative peers of Ireland and made a knight of St Patrick. Thereafter he was not especially politically active, but supported catholic emancipation and otherwise usually voted with the government in the house of lords. He was governor of Co. Donegal (1803–31) and custos rotulorum of Co. Clare (1808–32). Perhaps because of the disturbed state of Co. Meath, his inherited Slane estate suffered considerable neglect in the late 1790s, but from 1801 Conyngham made Slane Castle his main Irish residence, carrying out considerable renovations and employing the English agriculturalist Richard Parkinson to improve the demense's 500-acre farm.
The Conynghams were not particularly well-connected until Henry's wife Elizabeth became the mistress of George IV in 1820. (It was said that Henry owed his marquessate (1816) to his wife's earlier friendship with the then prince regent; that year he was also created Viscount Slane and earl of Mount Charles ). When George IV visited Ireland in August 1821 he stayed at Slane Castle, which underwent further renovations to cater for his arrival. Elizabeth made full use of her influence to further her family's position: her husband was given a UK peerage (Baron Minster of Minster Abbey, Kent) in 1821, appointed to the privy council, and made lord steward of the household (1821–30), constable and governor of Windsor Castle (1829–32), and promoted to full general in 1830. His twin, Francis Nathaniel Pierpoint Burton (1766–1832), was MP for Killybegs (1790–97) and for Co. Clare (1797–1808), and lieutenant governor of Lower Canada (1808–32), although he only actually served in that position in 1824–5. Henry Conyngham died 28 December 1832 at his house in Hamilton Place, Piccadilly, London, and was succeeded by his second son Francis Nathaniel.
Francis Nathaniel Conyngham (1797–1876), 2nd Marquess Conyngham , landlord, courtier and politician, was born 11 June 1797 in Dublin. Educated at Eton, he became known as Lord Francis Conyngham when his father was created Marquess Conyngham in 1816, and gained the courtesy title of earl of Mount Charles on the death of his unmarried elder brother, Henry Joseph Conyngham (1795–1824), who was tory MP for Co. Donegal (1818–24). Owing to his mother's influence, Francis was a page of honour to the prince regent until 1820 and afterwards first groom of the bed-chamber and master of the robes (1820–30); he often irritated fellow courtiers by flaunting his favour with the king. As MP for Westbury (Wiltshire) (1818–20) (a seat purchased by his father) and Co. Donegal (1825–31), he was a pro-catholic tory until 1830, and afterwards supported the whigs. He served as under-secretary of state for foreign affairs (1823–5) and lord of the treasury (1826–30). In 1832 he succeeded his father, entering the house of lords and serving as postmaster general (July–December 1834 and April–May 1835). Appointed to the privy council in 1835, he was lord chamberlain (1835–9) to William IV and having brought news of her accession to Victoria on 20 June 1837 was the first person to address her as 'your majesty'.
Ireland featured little in his political and social world, although he was MP for an Irish seat and one of the greatest landowners in the country, with large estates in counties Donegal (122,300 acres), Clare (27,613 acres), and Meath (7,060 acres); (he also held 9,737 acres in Kent). There were four distinct holdings in Donegal (Boylagh, Mountcharles, the Rosses and Stranorlar), the Clare estate was centred around Kilrush and Kilkee, and the Meath estate around Slane. Conyngham rarely visited them and left their running to agents, who had little interest in improving the holdings or in the welfare of tenants. During the Great Famine of the late 1840s, tenants on his lands in Clare and Donegal suffered serious distress and many were forced to quit their holdings. He was often regarded as one of the most infamous examples of the heartless absentee landlord. Evictions from his Clare estates continued into the 1860s, provoking a local catholic curate, Fr Sylvester Malone (qv), to write in protest the pamphlet Tenant wrong illustrated in a nutshell (1867). A commissioner from the London Times noted the wretchedness of his peasantry and reported claims that Conyngham had only visited his estates once and never replied to any correspondence or complaints sent to him. An obituary in the New York Times (19 July 1876) described him as an aristocrat 'of that stamp which precipitated the French revolution of 1789 – a selfish voluptuary, dead to all sense of the duty which devolved on him as steward of the great gifts entrusted to him'.
Conyngham was made a knight of St Patrick (1833), lieutenant-colonel of the Clare militia (1834), vice admiral of Ulster (1849–76) and lord lieutenant of Co. Meath (1869–76). Commissioned cornet in the army in 1820, he was promoted steadily to become a major-general in 1858, lieutenant-general in 1866 and full general in 1874. He died 17 July 1876 in London and was succeeded as third marquess by his eldest son George Henry Conyngham (1825–82).
In 1824 he married Lady Jane Paget (1798–1876), daughter of the 1st marquess of Anglesea. They had six children (two boys and four girls): his daughter Jane (1826–1900), Lady Churchill, was a lady of the bedchamber to Queen Victoria and one of her closest friends. His younger son Francis Nathaniel Conyngham (1832–80) was Liberal MP for Co. Clare (1857–9, 1874–80) and a supporter of home rule; he was also the first president of the Society for the Preservation of the Irish Language founded in 1876. A large collection of Conyngham family papers is held in the NLI.