King William IV was born at Buckingham Palace on 21 August, 1765, the third son of King George III of Great Britain and his wife Sophia, and younger brother of George, later King George IV. He entered the Royal Navy at fourteen, and served in America and the West Indies. He remained in the navy, reaching the rank of Admiral, until he retired in 1811. In 1789 he had been granted the title of the Duke of Clarence, with an allowance of £12,000 per year. A Whig, he rebelled against most of his father's Tory political stands, and favoured Catholic emancipation. Upon the death in 1818 of Princess Charlotte, the daughter of George IV, the remaining children of King George III were required to hastily arrange to secure the succession by marrying and producing heirs. William abandoned his mistress of ten years, the actress Mrs. Dorothea Jordan, and their ten children, and married Adelaide of Saxe-Coburg and Meiningen. They had two daughters, both of whom died in childhood.
When King George IV died in 1830, William became king. Considered something of an eccentric, King William IV occasionally raced his carriage through London or stopped to give lifts to passers-by. His eccentricies were greatly preferred to the profligacy of his antecedents and his short reign was a relatively popular one; his coronation cost one-tenth that of George IV and he famously walked from Parliament to Buckingham Palace through cheering crowds after a speech. He died on 20th June 1837 of pneumonia, and was succeeded by his niece Princess Victoria.