Who is Francis-William Austen from Jane Austen's Letters and what is their importance?

Francis-William Austen, born April 23, 1774, was educated at the Royal Naval Academy from 1786-1788 and served in the navy. He later married Mary Gibson. The couple had six sons and five daughters. After her death, he married Martha Lloyd. They had no children. Francis died on August 10, 1865.