East Prussia, therefore, had a sentimental importance in the eyes of the Prussian nobility. The Prussian Royal House, in particular, had toward this country an especial regard. Moreover, it was regarded by the Germans as a whole as their rampart against the Slav, a proof of the German power to withstand the dreaded Russian. That this sacred soil should now be in the hands of a Cossack army was not to be borne. The Kaiser acted at once. Large forces were detached from the west and sent to the aid of the eastern army. A new commander was appointed. He was General von Hindenburg, a veteran of the Franco-Prussian War who had been for some years retired. After his retirement he devoted his time to the study of East Prussia, especially the ground around the Masurian Lakes. He became more familiar with its roads, its fields, its marshes, its bogs than any of the peasants who spent their lives in the neighborhood of the lakes. Before his retirement, in the annual maneuvers, he had often rehearsed his defense against Russian invaders. Indeed report, perhaps unfounded, described his retirement to the displeasure of the Emperor William at being badly worsted in one of these mimic combats. He had prevented the country from being cleared and the swamps from being drained, arguing that they were worth more to Germany than a dozen fortresses. A man of rugged strength, his face suggesting power and tenacity, he was to become the idol of the German people. His chance had come. His army consisted of remnants of the forces of von Francois and large reinforcements sent him from the west. In all, perhaps, he had with him 150,000 men, and he had behind him an admirable system of strategic railways. The Russian High Command was full of confidence. Rennenkampf had advanced with the Army of the Niemen toward Koenigsberg, whose fall was reported from time to time, without foundation. Koenigsberg was in fact impregnable to armies no stronger than those under Rennenkampf's command. Samsonov with the Army of the Narev, had pushed on to the northeastern point of the lakes, and defeated the German army corps at Frankenau. Misled by his success, he decided to continue his advance through the lake region toward Allenstein. He marched first toward Osterode, in the wilderness of forest, lake and marsh, between Allenstein and the Lower Vistula. His force numbered 200,000 men, but the swamps made it impossible to proceed in mass. His column had to be temporarily divided, nor was he well informed as to the strength of his enemy. On Wednesday, the 26th of August, his advance guards were everywhere driven in. As he pushed on he discovered the enemy in great numbers, and late in the day realized that he was facing a great army.