The idea of a book of emblemata was suggested to Escher by the Dutch art historian G. J. Hoogewerff, director of the Dutch Historical Institute in Rome. An emblem is an allegorical illustration that combines an image with text in the form of a saying or poem. As an artistic idiom it reached its zenith in the 18th century, when numerous books were published, often with a didactic imperative. Hoogewerff himself composed the aphorisms, under the pseudonym A. E. Drijfhout, for Escher's modern version. While Escher makes a nod to the past by including traditional motifs such as the lute, his emblemata include references drawn from everyday life, such as a vase of flowers, a kite and steam roller, as well as exquisitely rendered scenes of the natural world. Although the project was not met with initial success, it did lead to Hoogewerff writing an ground-breaking article on Escher as a graphic artist for the journal Elsevier, which was published in 1931. Hoogewerff's effuse praise for the artist would make a significant contribution to Escher's reputation.