William IV (William Henry; 21 August 1765 – 20 June 1837) was King of the United Kingdom and King of Hanover from 26 June 1830 until his death in 1837. The third son of George III, William succeeded his elder brother George IV, becoming the last king and penultimate monarch of Britain's House of Hanover. William served in the Royal Navy in his youth, spending time in North America and the Caribbean, and was later nicknamed the "Sailor King". In 1789, he was created Duke of Clarence and St Andrews. In 1827, he was appointed as Britain's first Lord High Admiral since 1709. As his two older brothers died without leaving legitimate issue, he inherited the throne when he was 64 years old. His reign saw several reforms: the poor law was updated, child labour restricted, slavery abolished in nearly all of the British Empire, and the British electoral system refashioned by the Reform Act 1832. Although William did not engage in politics as much as his brother or his father, he was the last monarch to appoint a prime minister contrary to the will of Parliament. Through his brother Adolphus, the Viceroy of Hanover, he granted his German kingdom a short-lived liberal constitution. William was born in the early hours of the morning on 21 August 1765 at Buckingham House, the third child and son of King George III and Queen Charlotte. He had two elder brothers, George and Frederick, and was not expected to inherit the Crown. William ceased his active service in the Royal Navy in 1790. When Britain declared war on France in 1793, he was anxious to serve his country and expected a command, but was not given a ship, perhaps at first because he had broken his arm by falling down some stairs drunk, but later perhaps because he gave a speech in the House of Lords opposing the war. The following year he spoke in favour of the war, expecting a command after his change of heart; none came. The Admiralty did not reply to his request. He did not lose hope of being appointed to an active post. In 1798 he was made an admiral, but the rank was purely nominal. Despite repeated petitions, he was never given a command throughout the Napoleonic Wars. In 1811, he was appointed to the honorary position of Admiral of the Fleet. William's elder brother, the Prince of Wales, had been Prince Regent since 1811 because of the mental illness of their father, George III. In 1820, the King died, leaving the Crown to the Prince Regent, who became George IV. William, Duke of Clarence, was now second in the line of succession, preceded only by his brother, Frederick, Duke of York. When the Duke of York died in 1827, William, then more than 60 years old, became heir presumptive. Later that year, the incoming Prime Minister, George Canning, appointed him to the office of Lord High Admiral.

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