William IV (William Henry; 21 August 1765 – 20 June 1837) was King of the United Kingdom of Great Britain and Ireland and of Hanover from 26 June 1830 until his death. William was the third son of George III and the younger brother and successor to George IV. Since 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 labor restricted, slavery abolished in nearly all the British Empire, and the Reform Act 1832 refashioned the British electoral system.