Fairies became a popular theme in art and literature in the early 20th century following the releases of The Coming of the Fairies by Sir Arthur Conan Doyle , Peter Pan by J.M. Barrie , and the fairy @-@ themed work of Australian Ida Rentoul Outhwaite . Queen Mary made such themes even more popular by sending Outhwaite postcards to friends during the 1920s . In 1918 , Barker produced a postcard series depicting elves and fairies .