The First World War began for Russia on August 1, 1914. In mid-1915, “Russian Poland” was occupied and troops were taken away under the command of the “Oberbefehlshaber Ost” and “Russian Poland” became Warsaw General Government. The ‘Oberbefehlshaber Ost’ only has command over the Njemen-Armee, the 10th Army and the 12th Army. A large part of the Baltic Area is still occupied with this force: on August 17, 1915 the 10th Army of Hindenburg conquered Kaunas. The advance stops at the end of 1915 just before Riga. The front line is then roughly the Riga-Jakobstadt-Dünaburg line. Riga is occupied much later – September 3, 1917.