Coningsby, Thomas (1657–1729), Baron Coningsby of Clanbrassil and earl of Coningsby , lord justice and officeholder, was born 2 November 1657, only son and heir of Humphrey Coningsby of Hampton Court, Herefordshire, and his wife Lettice Loftus (daughter of Sir Arthur Loftus of Rathfarnham, Co. Dublin, and sister of Adam, 1st Viscount Lisburne). As a firm whig and ardent supporter of the revolution of 1688, Coningsby began to display a keen interest in Irish affairs, initially in the English convention parliament of 1689, where he was appointed to committees to inquire into the delays in relieving Derry and to consider raising money from Irish forfeited estates. He also took part in preparing the bill of attainder. During the second session he was appointed to the committee for the relief of refugees, and acted as teller for adjourning the debate about Commissary Shales. He served also as a commissioner for excise appeals in Ireland (1689–90). His connection with Ireland was enhanced by his appointment (30 May 1690) as joint receiver and paymaster-general of the forces for the reduction of Ireland, his fellow appointee being Charles Fox. After this important appointment, Coningsby accompanied William III (qv) to Ireland (June 1690), and is traditionally known as having tended William's shoulder wound at the Boyne, thus earning himself high favour with the king. On 4 September 1690 Coningsby and Henry Sidney (qv) were appointed the first Williamite lords justices of Ireland. He served in government until August 1692, sharing the unenviable task of governing a country divided by war, and figuring prominently in the final negotiations and signing of the treaty of Limerick (October 1691). His period as a lord justice earned him many enemies amongst Irish protestants, not least because of his connection with this unpopular treaty. He came in for bitter attack in the Irish parliament of 1692, being accused of maladministration and arbitrary government, illegal trade, embezzlement of stores, and appropriation of forfeited estates. It was believed in both English and Irish political circles that the real reason for the prorogation of that parliament was to protect Coningsby and other courtiers from attempted impeachment.
Coningsby's troubles in relation to Ireland did not cease, and in 1693 his opponents took their grievances to the English parliament, where an attempted impeachment was finally defeated (January 1694). The suspicion of illegal activity was heightened by the granting of a pardon by William III (May 1694) to Coningsby and his fellow lord justice, Sir Charles Porter (qv), for their actions while governing Ireland. William held Coningsby in high regard, creating him Baron Coningsby of Clanbrassil (17 April 1692), and thus enabling him to sit in the Irish house of lords. He was rewarded further (December 1692) by being made sole vice-treasurer and treasurer-at-war for Ireland. In 1698 he was appointed sole receiver and paymaster-general, vice-treasurer, and treasurer-at-war, giving him total control of the four offices associated with the vice-treasury. This appointment was not without criticism. Charles Fox petitioned the king, claiming that he had carried out most of the work for the previous nine years. Coningsby remained in these offices until 1710. In January 1693 he was appointed to the Irish privy council; he also received a large grant out of the forfeited estates.
After the attacks upon him in 1692–4, Coningsby distanced himself from direct involvement in Irish affairs in order to avoid any further recriminations. When his name arose in the Irish parliament of 1695, the government managed to prevent further action against him. Coningsby executed his Irish offices by deputy, spending his time involved in English affairs, and campaigning on the continent with the king. With William's death (1702), Coningsby lost favour at court, only returning to prominence after 1715, when his enthusiasm for the Hanoverian succession earned him his English peerages: Baron Coningsby of Coningsby, Co. Lincoln (1716), and earl of Coningsby (1719). His later years were dominated by legal problems over his estate in England. He died 1 May 1729.
Coningsby married (1675) Barbara, eldest daughter of Ferdinando Gorges of Herefordshire, a Barbados merchant. They had seven children; the marriage was dissolved by act of parliament (1697). In 1698 he married Frances Jones (1674–1715), younger daughter of Richard, earl of Ranelagh (qv), to the disapproval of the latter. They had three children. Coningsby was MP for Leominster borough (1679 × 1710, 1715–16) until elevated to the English peerage. His Irish peerage became extinct with the death without issue (18 December 1729) of his grandson by his first marriage.