In 1870, he quit his job at the "Kreuzzeitung" and became theater critic for the liberal "Vossische Zeitung" (newspaper). This job he kept until retirement. He had already written about Prussia's war against Denmark and the Austro-Prussian War. Then he went to write about the Franco-Prussian War in 1870 and was taken prisoner. He remained in French captivity for three months. His experiences there are set down in "Kriegsgefangen Erlebtes 1870 (1871)"; subsequently he published his observations on the campaign in "Der Krieg gegen Frankreich 1870-71" (1874-1876).