Eugenia Stanhope, the impoverished widow of Chesterfield's illegitimate son, Philip Stanhope, was the first to publish the book "Letters to His Son on the Art of Becoming a Man of the World and a Gentleman" (1774), which comprises a thirty-year correspondence in more than 400 letters. Begun in 1737 and continued until the death of his son in 1768, Chesterfield wrote mostly instructive communications about geography, history, and classical literature, with later letters focusing on politics and diplomacy, and the letters themselves were written in French, English and Latin to refine his son's grasp of the languages.