Robert Fay at his own website:
The writer-diplomat tradition, though largely ignored in the history of letters, has been critical to the development of many European and Latin American writers. Eight poets with diplomatic experience, including Octavio Paz and Czeslaw Milosz, have won the Nobel Prize for Literature. Tadié references France’s great tradition, which reached its apex in 1937 when 50 percent of the diplomats from the Quai d’Orsay (The French Foreign Ministry) were published authors.
Mexico, among Latin American countries, has the most prestigious tradition with Carolos Fuentes, Paz and Sergio Pitol, a collection of writers so mighty, that one might assume there was a magical current uniting the diplomatic craft and literature.
Geoffrey Chaucer was one of the first literary men to practice these dual arts. He worked for the English Royal Service and conducted diplomatic missions on behalf of King Edward III in France, Spain and Italy in the 1360s.
More here.