The inspiration for the unusual composition came from Hypnerotomachia Poliphili ("Poliphilo's Dream of the Strife of Love"), an unusual 15th century novel probably by Francesco Colonna. The novel's main character meets an elephant made of stone carrying an obelisk, and the accompanying woodcut illustration in the book is quite similar to Bernini's design for the base for the obelisk. The curious placement of the obelisk through the body of the elephant is identical.