"The Mares of Diomedes" was the first piece of American sculpture purchased by the Metropolitan Museum of Art in New York. This work was shown at the 1904 World's Fair in St. Louis, where Borglum won a gold medal. Despite the classical title, which refers to one of the Labors of Hercules, the equine subject and energy of this piece seem to allude more closely to Borglum's western upbringing.