William Augustus Montagu Vice - Admiral Sir William Augustus Montagu , KCH , CB ( c . 1785 – 6 March 1852 ) was a senior and successful officer of the British Royal Navy during the French Revolutionary and Napoleonic Wars who served in a number of sea battles and was also in command of the naval brigade in the brief land campaign to capture Île de France in 1810 . During his service he was present at the capture of numerous French frigates and later served in the War of 1812 . After the end of the Napoleonic Wars he remained in service and commanded several ships in the Mediterranean before he retired from active service in 1837 . He remained a commissioned officer and later rose through the ranks to become a vice - admiral . For his services he was knighted in the Royal Guelphic Order and made a Companion of the Order of the Bath . Family background . Born in approximately 1785 , William Augustus Montagu was an illegitimate son of John Montagu , 5th Earl of Sandwich . William is thought to be named after his uncle , William Augustus , who died at Lisbon in 1776 . His grandfather was John Montagu , 4th Earl of Sandwich , who served three terms as the First Lord of the Admiralty , to 1783 . Military and Parliamentary Service , and Awards . Montagu joined the army young , going to sea aged 11 in 1796 as a volunteer on HMS " Glatton " commanded by Captain Henry Trollope . Montagu remained with Trollope when he moved , first to HMS " Russell " in which Montagu saw action at the Battle of Camperdown and subsequently HMS " Juste " . In late 1800 , Montagu was commissioned as a midshipman and joined the frigate HMS " Sirius " . In " Sirius " he was present at the capture of " Dédaigneuse " and then moved into the brig HMS " Dasher " for four years , spent in the West Indies . In 1804 Montagu returned to Europe as a lieutenant and the following year was promoted to commander . In 1807 , Montagu became a post captain and took command of the small frigate HMS " Terpsichore " in the Indian Ocean . In March 1808 , " Terpsichore " was attacked by the larger French vessel " Sémillante " and despite heavy losses , Montagu was able to outfight his opponent although he could not capture her . Soon afterward Montagu moved to HMS " Cornwallis " and served in the East Indies , forming part of the squadron that captured Amboyna from the Dutch and seized two Dutch frigates in the harbour . By 1810 , Montagu was established in the Indian Ocean and was selected from the captains assembled for the Invasion of Île de France to lead the naval brigade , a force of sailors and Royal Marines deployed on shore to support the British Army forces leading the attack . During the assault Montagu fought well and was commended after his brigade assisted in breaking the French resistance around the capital Port Napoleon . In September 1812 , Montagu returned to Europe to command HMS " Niobe " in the Channel Fleet , later serving off the United States during the War of 1812 and in Portuguese waters . In June 1814 , with the war coming to an end , " Niobe " was paid off and Montagu was in reserve until 1819 , when he took command of HMS " Phaeton " in Halifax , Nova Scotia . Between 1818 and 1820 he sat in Parliament for Huntingdon . In 1822 , " Phaeton " was paid off and Montagu was in reserve until 1834 , marrying Anne Leeds , daughter of Sir George William Leeds in 1823 . Montagu took command of HMS " Malabar " in 1834 and remained in her until 1837 in the Mediterranean . This was his final commission and when he was placed in reserve again in 1837 he did not return to the sea . He remained in the Navy however and slowly rose through the ranks , becoming a rear - admiral in 1841 and a vice admiral in 1851 . Montagu was knighted in 1830 in the Royal Guelphic Order and in 1832 became a Knight Commander , accompanied by a Knight Bachelor award for use in Britain . He had previously been made a Companion of the Order of the Bath in 1815 at the end of the war . He died at Ryde , on the Isle of Wight in March 1852 .