I. Henry, Lord Sidmouth, an English statesman, born May 30, 1757, died Feb. 15, 1844. He was the son of Dr. Anthony Addington of Reading, known as the author of treatises on scurvy and on the mortality of beasts, and for his attempt in 1778 to establish a political alliance between the earl of Bute and the earl of Chatham, whose physician he was. This connection with Lord Chatham led to an intimacy between Henry Addington and the younger William Pitt, who induced him to enter parliament in 1784. He was called to the bar in the same year, but never practised. In 1789 he was elected speaker, and continued to support Pitt, but voted against him on the slave question, favoring a gradual emancipation. In 1801 Pitt resigned and Addington took his place as chancellor of the exchequer and first lord of the treasury, and formed a new ministry. He aided in forming the treaty of Amiens in 1802, the objectionable clauses in which were vigorously attacked by Windham and Grenville. But in 1803, when peace was considered dishonorable, he supported a war policy. The prince of Wales, afterward George IV., had a personal dislike to Addington, who was regarded as the chief of the special friends of George III., and the illness of the latter gave the prince opportunity to show his animosity.

In 1804 Addington resigned, and the king created him a peer by the title of Viscount Sidmouth (Jan. 12, 1805), and appointed him president of the council, which office he resigned in July. After Pitt's death, Lord Sidmouth entered the ministry of Grenville and Fox (Feb., 1806, to March, 1807), first as lord privy seal and afterward as president of the council. In 1812 Lord Sidmouth was appointed secretary for the home department in Lord Liverpool's ministry. In 1822, on the death of Lord Castlereagh, he resigned his office, but at Lord Liverpool's request retained his seat in the cabinet two years longer.

II. Henry Unwin, an English diplomatist, a relative of the preceding, born March 24, 1790, died in London, March 6, 1870. He entered the foreign office after leaving Winchester college, and was for upward of 30 years in the diplomatic service in various countries, including the United States, whither he was sent in 1822, and again in 1826. He was under-secre-tary of state from 1842 to 1854, when on his retirement he was made privy councillor.