In his seminal Traité medico-philosophique sur l'aliénation mentale of 1801, the eminent French alienist, Philippe Pinel (1745–1826) held that ‘the most secure and perhaps only guarantee to maintain sanity, good morals and order’ in asylums should be ‘mechanical work rigorously applied’. This image reflects Pinel's therapeutic philosophy. It shows female patients exercising with guns made of wood in the yard of the psychiatric ward of the Berlin Charité around 1810. The image appeared in a psychiatric treatise by Ernst Horn. He had studied in Jena and Gottingen, and was appointed professor at the Military Academy in Berlin in 1806. Horn was also given responsibility for the psychiatric ward in the Charite hospital, where he prescribed the type of therapeutic intervention illustrated in the picture. It was not a manifestation of Prussian militarism but stemmed from his theories on the origin of mental illness. Horn was convinced that orderliness and regularity helped to smooth emotions and to ‘rectify’ reason. Exercise was held to be especially important. Horn, along with J. B. Langermann and J. C. Reil, was one of the first psychiatrists in the German-speaking countries.