King William IV

William IV (August 21, 1765 – June 20, 1837) was King of the United Kingdom of Great Britain and Ireland and of Hanover from 26 June 1830 until his death. William, the third son of George III and younger brother and successor to George IV, was the last king and penultimate monarch of Britain's House of Hanover.

Background
He was the answer of a question at the National Archives' pop quiz terminals.

Appearances
William IV is mentioned only in Fallout 3.