Sir Henry came from a family with a seafaring tradition and went to sea in 1800 at age 14 aboard the 32-gun frigate, HMS Maidstone. And being the son of Admiral Duncan gave him the internal patronage he needed to rise quickly in rank. He was already a lieutenant by his father’s death in 1804 and was quickly appointed commander in November 1804. He was promoted to post rank while serving under Admiral Sir Cuthbert Collingwood in 1806.
By the time our story takes place in 1813, he was a 27 year old captain of seven year’s seniority commanding the HMS Imperieuse, a 38-gun frigate previously commanded by Lord Cochrane and which was formerly the Spanish Medea taken as a prize when Captain Graham Moore’s squadron seized the Spanish treasure fleet on October 5, 1804.