East Prussia

In a single year of the war, 1914–1915, Russian troops overran two-thirds of East Prussia, the most eastern province of the German Reich. It would remain the only meaningful occupation of German territory. In August the Reich’s eastern border had remained only weakly defended in keeping with German operational plans so that the troops could first conduct a decisive attack in the West against France. Yet the Russian army mobilized more quickly than the German plans had envisioned. The …