The fourth Duke of Hamilton was killed in a duel with Lord Mohun on Sunday, Nov. 15, 1712, under very painful circumstances, causing at the time the most intense public interest and the fiercest political controversy. Hamilton, a leader of the Tory party, celebrated for his strenuous opposition to the Scottish Union, had just been appointed Ambassador to France; and it was asserted that Mohun, a Whig Lord, a violent and dissipated man, already involved in a bitter family quarrel with the Duke, had brought about the duel from party motives. This has since been frequently contradicted, and the animosity which led to the duel ascribed to some angry words spoken in the course of a Chancery suit. However this maybe, the duel was one of unparalleled ferocity. The opponents met in a sequestered spot near the Serpentine, behind Kensington Palace. Colonel Hamilton, of the Foot Guards, attended the Duke, and General Macartney, Lord Mohun. The seconds fought, according to a French fashion then in vogue, as well as the principals. Mohan and Hamilton both fell mortally wounded. The report immediately spread that Macartney had murdered the Duke by stabbing him over the shoulder of Colonel Hamilton; but in the sequel this charge of treachery utterly failed to be established. Macartney escaped to Holland, where he remained till the accession of George I. He then returned and surrendered himself. His trial ended in an acquittal of murder; he was restored to his rank, and gratified with the command of a regiment. One of the striking incidents of this tragedy was that, immediately after its occurrence, the young Count d'Arran, the Duke's illegitimate son, by Lady Barbara Fitz-Roy (a daughter of King Charles II.), felt so keenly the death of his father that he hastened to Antwerp and challenged Macartney to mortal combat —a challenge which was at once declined.

Source: The Illustrated London News, No.2254—Vol. LXXXI, Saturday, July 15, 1882, p.70