overwhelming rapidity. With relentless energy Von
Hindenburg now used his intimate knowledge of the territory in which he
was fighting. Wherever he knew the most hopeless territory to be, there
he drove the Russians. Mazurian swamps and lakes did all that he had
ever claimed they would do and more. They swallowed up his enemy by the
thousand, they engulfed his guns and sucked in his horses.

Within a week after Von Hindenburg had reached East Prussia the problem
of the Narew Army had changed from how to extend its advance most
quickly to how to escape from this bottomless pit along the few
inadequate lines of escape that were left. The morale of this Russian
army was broken. For even the most stolid Russian peasant soldier, whom
neither the roar of guns nor the flash of bayonets could move, quaked at
seeing whole companies and batteries disappear, in less time that it
takes to tell about it, in the morasses of a country without firm roads
and a minimum of solid ground.

On the last day of August, 1914, thousands of Russians had laid down
their arms and were sent back into central Germany. Of Russian armies of
more than a quarter of a million nearly a hundred thousand fell into
German hands. Almost half as many more were killed or wounded. The
Russian commander in chief was killed on August 31, 1914. Only one corps
escaped by way of Ortelsburg and Johannisburg, while scattered fragments
of varying size fought their way out, some into north Poland and some
into the protecting arms of the Niemen Army. Most of the guns of
Samsonoff's army were either captured by the Germans or lost in the
swamps. This one week's battle among the Mazurian lakes is known now as
the Battle of Tannenberg, so named after a small town west of and
halfway between Soldau and Allenstein.

Without giving his troops any rest Von Hindenburg now turned against
Rennenkampf's forces. But, in spite of the rapidity of movement, the
German commander could not accomplish all that he had set out to do.
Apparently his plan was now to strike north past Angerburg and Goldap to
Gumbinnen, or possibly even to Eydtkuhnen in order to cut off the
retreat of the army of the Niemen and drive them in a southerly
direction to their destruction in the Mazurian lakes, just as he had
done in his easterly drive against the Narew Army. But Rennenkampf was
too quick. He recognized the danger that threatened him through the
defeat of Samsonoff's forces and he began his retrea