achieved by Henry Pelham, who resigned on 10 February 1746 but returned to office two days later (12 February) when Lord Bath had been invited to form a ministry but failed to do so. The shortest interval where an intervening ministry had been formed was achieved by Lord Melbourne, who was out of office after being dismissed on 14 November 1834, but returned 155 days (under six months) later, following the end of successor Robert Peel's first ministry on 18 April 1835. Number of terms A prime minister's "term" is traditionally regarded as the period between the appointment and resignation, dismissal, or death, with the number of general elections taking place in the intervening period making no difference. The only prime minister to serve four terms under that definition was William Ewart Gladstone: 3 December 1868 – 20 February 1874 23 April 1880 – 23 June 1885 1 February–25 July 1886 15 August 1892 – 5 March 1894 Three prime ministers have served three terms: The Earl of Derby 23 February 1852 – 17 December 1852 20 February 1858 – 11 June 1859 28 June 1866 – 25 February 1868 The Marquess of Salisbury 23 June 1885 – 28 January 1886 25 July 1886 – 11 August 1892 25 June 1895 – 11 July 1902 Stanley Baldwin 22 May 1923 – 22 January 1924 4 November 1924 – 4 June 1929 7 June 1935 – 28 May 1937 Thirteen prime ministers have served two terms: Winston Churchill, Benjamin Disraeli, Ramsay MacDonald, The Viscount Melbourne, The Duke of Newcastle, Lord Palmerston, Robert Peel, William Pitt the Younger, The Duke of Portland, The Marquess of Rockingham, Lord John Russell, The Duke of Wellington, and Harold Wilson. Terms of PMs and reigns of sovereigns The office of prime minister has coincided with the reigns of eleven British monarchs (including a Regency during the incapacity of George III from 1811 to his death in 1820), to whom the prime minister has been constitutionally head of government to the sovereign's headship of state. Until 1837, the death of a sovereign led to Parliament being dissolved within six months which led to a general election. The results of such elections were: 1727 — Robert Walpole held 1761 — the Duke of Newcastle held 1820 — Lord Liverpool held 1830 — the Duke of Wellington defeated, Lord Grey appointed 1837 — Lord Melbourne held Served under most