Earl Horter began his career as an engraver of stock certificates and illustrator for a Philadelphia advertising agency. He studied etching at the Sketch Club in Philadelphia under James Fincken (1860–1943), and began to exhibit at the Pennsylvania Academy of the Fine Arts in 1915, the same year that he won a silver medal at the Panama‑Pacific International Exposition in San Francisco. James Abbott McNeill Whistler (1834–1903) and Joseph Pennell (1857-1926) were important influences on Horter’s early work. His mature style was profoundly influenced by the modernism, especially Cubism that he saw during his extensive travels in Europe. In addition to creating his own distinguished body of work, he amassed an important collection of avant-garde art that was exhibited at the Philadelphia Museum of Art and Arts Club of Chicago in 1934. The exhibition, Mad for Modernism: Earl Horter and His Collection, held at the Philadelphia Museum of Art in 1999, traced the history of Horter’s collection and included a selection of the artist’s own works; the exhibition’s catalogue by Innis Howe Shoemaker is the standard reference on the artist (Mad for Modernism: Earl Horter and his Collection (Philadelphia: Philadelphia Museum of Art, 1999).