Henry William Greville was the third son of Charles Greville and Lady Charlotte Cavendish-Bentinck (d.1862), daughter of William HenryCavendish-Bentinck, 3rd Duke of Portland (1738-1809). He was born 28 October, 1801, and died unmarried, on 12 December, 1872. His brother was the diarist, Charles Greville, whose Leaves from a Diary was published after his death.
Inspired by a true story, Invincible recounts the last 48 hours in the life of Marc-Antoine Bernier, a 14-year-old boy on a desperate quest for freedom.