Admiral of the Red Sir William Cornwallis, (10 February 17445 July 1819) was a Royal Navy officer. He was the brother of Charles Cornwallis, the 1st Marquess Cornwallis, British commander at the siege of Yorktown. Cornwallis took part in a number of decisive battles including the Siege of Louisbourg in 1758, when he was 14, and the Battle of the Saintes but is best known as a friend of Lord Nelson and as the commander-in-chief of the Channel Fleet during the Napoleonic Wars. He is depicted in the Horatio Hornblower novel, "Hornblower and the Hotspur".