 Complete the following phrase:  He returned to London and became a pupil under A. B. Clay, but was back in Germany a few years later, this time studying at the Düsseldorf school of painting in Europe, where he studied under the German military artist, Emil Hünten, himself an ex-pupil of Horace Vernet, and at the time military and historical painter to the Prussian emperor. Under Hünten, Crofts talent as a military painter grew, and in 1874, he exhibited Retreat, representing an episode in the Franco-Prussian War during the 