Clements, Nathaniel (1705–77), treasury official, property developer, architect, and MP, was third of four surviving sons of Robert Clements (1664–1722), landowner, of Rathkenny, Co. Cavan, and Abbotstown, Co. Dublin, and his wife Elizabeth (d. 1742), daughter of Gen. Theophilus Sandford of Moyglare, near Maynooth, Co. Kildare. Robert Clements was attainted by the Jacobite parliament in 1689, but was restored to his estates on the accession of William III (qv) and later appointed teller of the Irish exchequer; he was also MP for Newry (1715–22). Nathaniel was MP for Duleek, Co. Meath (1728–60), Cavan borough (1761–8), Co. Leitrim (1768–76) and Carrick, Co. Leitrim (1776–7), and high sheriff of Co. Cavan (1731), Co. Donegal (1752) and Co. Leitrim (1764). He held an extensive array of sinecures, including lucrative customs places for the ports of Dublin and Carrickfergus. Like his elder brother Theophilus (1687–1728), MP for Cavan borough (1713–28), he followed his father into the treasury and on Theophilus's death succeeded him as teller of the exchequer (1728–55). Theophilus was a poor administrator and it took Nathaniel some years to clear up the financial mess he had made. In 1731 he obtained the lucrative position of agent to military pensioners, which generated commissions averaging £2,000 a year in the 1740s and early 1750s. By the mid 1750s his income from all official sources was reckoned at £8,000 a year, although this declined after 1755 when government cast a closer eye on his earnings. However, in 1756 he became agent for the regiments on the Irish establishment serving abroad, which generated considerable commissions. He owed much of his advancement to the influence of his distant relation Luke Gardiner (qv), who had managed to overcome the administration's suspicions of Irish officeholders, and from about 1749 to 1777 he acted as a private banker to every Irish administration. For almost fifty years he was the dominant figure in Irish financial administration – effectively the Irish chancellor of the exchequer – a position that gave him access to leading parliamentarians, lords lieutenant, members of the royal family, and royal mistresses. He amassed a large fortune by manipulating treasury balances, the disposal of which gave him considerable influence that was all the greater for the subtle manner in which he used it.
He and his wife enjoyed a reputation as people of wealth, taste, and elegance, and were lavish hosts. Clements and Luke Gardiner cooperated in building the grand residential quarter of Henrietta St., Dublin, in the early 1730s, and he designed his own house at 7 Henrietta St. He was also involved in the development of Sackville St. with the architect Richard Castle (qv) in the early 1750s. On receiving the lifetime appointment of ranger of the Phoenix Park and master of the game (1751), Clements designed and built the Phoenix lodge (1751–4), which became the viceregal lodge in 1782 and subsequently Áras an Uachtaráin, the residence of the presidents of Ireland. A talented architect, he is credited with an important part in developing the Palladian villa-farm style of Irish country houses. In the 1750s and ‘60s he may have designed or advised on the design of several country houses, for example at Brooklawn and Colganstown in Co. Dublin, at Belview, Co. Cavan, Beauparc, Co. Meath, and at Newberry Hall and Lodge Park, Co. Kildare, all of which show the influence of his mentor Richard Castle. His residences were Manor Hamilton and Bohey, Co. Leitrim; Ashfield, Cootehill, Co. Cavan; and Woodville, Lucan, Co. Dublin.
From the 1730s and to about 1760 he bought large amounts of landed property in Co. Cavan, Co. Donegal, and Co. Leitrim (including the parliamentary borough of Carrick on Shannon). Much of this land was bought from relatives or in-laws in financial difficulties, and Clements usually obtained it on favourable terms. By 1760 he had spent £70,000 to acquire 85,000 acres, giving him a rental income of £6,000; added to his income from office, this made him one of the wealthiest men in Ireland. This property gave him control over several parliamentary seats, and the marriage of his four daughters to Irish MPs further strengthened his political influence in Cavan, Leitrim, and Donegal. Connected by marriage with the Gore family, in parliament he sided with the faction of his brother-in-law, Anthony Malone (qv), which in the 1750s supported Henry Boyle (qv) and the Ponsonbys. During the money bill crisis of 1753 Clements attempted to placate both sides, by voting with the government while throwing his influence and financial resources behind the Patriot opposition. This double-dealing rather vexed the Irish administration, which intimated that he would be dismissed from the treasury. In September 1753 and October 1754 he was summoned to London and lectured sternly for his duplicity. He was asked for assurances about his future conduct and pledged his loyalty to the Castle. By 1754 the controversy had crystallised into a straight choice between the retention of Clements or of Dorset (qv), the viceroy. Archbishop George Stone (qv) claimed that Clements had been the dominant behind-the-scenes influence during the money bill crisis and pressed hard for his dismissal, but London was not prepared to risk the reaction that might bring, and the decision in favour of Clements was a celebrated victory for the Patriots. Stone continued to attempt to wrest the treasury from Clements for many years, but was ultimately unsuccessful.
On Gardiner's death (1755) Clements became deputy vice-treasurer and deputy paymaster general of Ireland, functions he had effectively performed for several years beforehand. With the reorganisation of the Irish treasury in October 1755, Clements gave up his place as teller of the exchequer to Sir Henry Cavendish (qv) in that month for an appointment as deputy vice-treasurer, which entailed some financial loss. Partly to regain the levels of income he had enjoyed before 1755, he became senior partner in the banking firm Clements, Malone, & Gore. Established 3 July 1758, it was the first Irish bank to pay interest on deposits and to make advances against bonded securities. It failed in November 1759 – the only major financial undertaking by Clements that proved unsuccessful. The bank's debts were about £75,000, and although Clements was in a position to repay his share, the other partners were not. Many MPs criticised the bank for overreaching itself and argued that its partners' property should be used to defray the public's losses, but the administration took a softer line and sponsored legislation establishing a phased plan of repayment and prohibiting the holders of public funds from engaging in banking. The failure encouraged Clements to engage in some financial retrenchment, and afterwards he made only one small purchase of land.
Although his opposition to the Newcastle ministry (1757–62) earned him the displeasure of George II, he was appointed to the Irish privy council c.1759. For the rest of his career he supported the government. He voted for a bill allowing catholics to purchase land mortgages in 1762 and for further catholic relief in 1774. His wealth and political influence would normally have secured him a peerage but he never sought one, since it would have meant resigning from the treasury. He died 26 May 1777 in Dublin. Clements was a widely respected administrator and the lord lieutenant, Buckingham (qv), lamented the death of a man ‘not easily replac'd’ (quoted in HIP, iii, 429).
His contribution to public affairs was almost always behind the scenes. Although he attended parliament regularly, he rarely spoke: Stone claimed that he was ‘incapable . . . of speaking three sentences in public’ (ibid., 428). Just as he was often underestimated by contemporaries, so Clements has been underestimated by historians: he was essentially a man of business who left few written traces of his work and influence. However, he brought continuity, experience, and great expertise in public financing to the Irish administration, and was one of its most important and influential officials.
He married (31 January 1729) Hannah, daughter of the Rev. William Gore (1679?–1732), dean of Clogher (1716–24) and Down (1724–32); they had three sons and four daughters. The eldest son, Robert (1732–1804), MP for Co. Donegal (1765–8, 1776–83) and Carrick (1768–76), became 1st Baron Leitrim (1783) and earl of Leitrim (1795), and was one of the original twenty-eight representative peers elected at the time of the union. The second son, William (1733–70), was MP for Baltimore, Co. Cork (1761–8); the third son, Henry Theophilus (qv), succeeded Nathaniel as deputy vice-treasurer.