John James Hamilton, 1st Marquess of Abercorn (Ire) (July 1756 – 27 January 1818) was an Irish peer and politician. Background and first marriage He was born in July 1756, the posthumous son of Captain Hon. John Hamilton and his wife Harriet, and grandson of James Hamilton, 7th Earl of Abercorn, and baptized at St George's, Hanover Square. He was educated at Harrow from 1770 to 1771. He was admitted to the Inner Temple on 15 June 1773, but did not remain there long; he was admitted to Pembroke College, Cambridge on 30 July 1773. He matriculated at Michaelmas and received his MA in 1776. There he became the friend of William Pitt the Younger, a connection that would serve him well in later years. He married Catherine Copley (died 13 September 1791), daughter of Sir Joseph Copley, 1st Baronet, on 20 June 1779 at St Marylebone. They had five children: Lady Harriet Margaret Hamilton (1780–1803), died unmarried. Lady Maria Hamilton (1782–1814), died unmarried. Lady Catherine Elizabeth Hamilton (1784–1812), married George Hamilton-Gordon, 4th Earl of Aberdeen and had issue. James Hamilton, Viscount Hamilton (1786–1814), married Harriet Douglas, granddaughter of James Douglas, 14th Earl of Morton and had issue. Lord Claud Hamilton (1787–1808), died unmarried. House of Commons Hamilton went abroad in about 1781, and returned in the late summer of 1783. Through the influence of John Buller, his wife's uncle, he was returned as a Tory Member of Parliament for East Looe in December, taking the seat vacated by William Graves. His maiden speech was in opposition to the East India Bill of the Fox-North Coalition. He was naturally a supporter of his friend Pitt's first ministry. At the 1784, he was put in for St Germans, another Cornish borough, by his half-brother Edward Eliot. Though deeply attached to Pitt, he possessed great independence of character and something of his uncle's stiff pride. A staunch supporter of Warren Hastings, he spoke in 1788 against a bill to regulate (and thereby sanction) the slave trade, and in favour of its abolition. On 9 October 1789, he succeeded his childless uncle as Earl of Abercorn, and entered the House of Lords as Viscount Hamilton. House of Lords He was created 1st Marquess of Abercorn on 15 October 1790, doubtless due to his political connections. His first wife died in 1791, and he married his first cousin, Lady Cecil Hamilton, daughter of Rev.