Were William IV and Napoleon alive at the same time?
Yes. William IV and Napoleon were alive at the same time for 51 years, from 1769 to 1821.
William IV was 3 when Napoleon was born.
William IV was 55 when Napoleon died, aged 51.
William IV
King of the United Kingdom and Hanover from 1830 to 1837
Born 21 August 1765 · died 20 June 1837, aged 71
Napoleon
French military leader, French Emperor 1804–1814 and again in 1815
Born 15 August 1769 · died 5 May 1821, aged 51