In 1909 Max Ernst had enrolled at the University of Bonn to study history, philosophy and literature but soon abandoned his studies. It was during this time, however, that he first came into contact with the avant-garde through August Macke, who introduced him to the poet Apollinaire, and artists such as Delaunay and Kandinsky. Without any formal artistic training, Ernst absorbed the spirit and style of these artists, experimenting with the formal principles of the cubists and expressionists but singularly avoiding identifying with any one group. He was also deeply influenced by the fantasies of the great Flemish masters Bosch and Breughel, and the painters of his native Rhineland, such as Grünewald. Feldarbeit an der Parkmauer in Brühl clearly displays, in its sinous forms and planes of colour, the influence of his great friend Macke, but also in some senses presages the artist's later work.
Walter Hopps has written of this early period in Max Ernst's art: 'Ernst's earliest Expressionist art, displaying the bright, even lurid colours common to his mode, evolved from a sophisticated employment of Cubist-like structure. Referential images... evince a vivid dramatic tension well beyond those found in the more pastoral works of his immediate circle. In turn, many assertive images within Ernst's Expressionist period pre-figured those found in his later Dada and Surrealist art' (W. Hopps, in exh. cat. Max Ernst, Dada and the Dawn of Surrealism, Munich and New York, 1993, p. 10).