Headquarters reported that the Tenth Russian Army, consisting
of at least eleven infantry and several cavalry divisions, had
been driven out of its strongly fortified positions to the east of
the Mazurian Lake district, forced across the border, and, having
been almost completely surrounded, had been crushingly defeated.
In fact, however, fighting continued as part of the same action
until the 21st of February, 1915, when the pursuit of the defeated
army ended.

The forces engaged in this titanic conflict were the Russian Tenth
Army, consisting, according to the Russian version, of four corps,
under General Baron Sievers, and the German East Prussian armies,
under General van Eichhorn, operating on the north on the line
Insterburg-Loetzen, and General van Buelow on the line Loetzen-Johannisburg
to the south of Van Eichhorn. Sources favorable to the Allies represent
the strength of General Sievers's army as 120,000 men. They assert
that the total German force consisted of nine corps, over 300,000
men. These are said to have included the Twenty-first Corps, which
had been with the Crown Prince of Bavaria in the west; three reserve
corps, also from the west; the Thirty-eighth and Fortieth Corps,
new formations, from the interior of Germany; the equivalent of
three corps from other sections of the eastern front; and a reserve
corps of the Guard. The German official description of the battle
credits the Russians with having had in this sector of the battle
front in East Prussia at the beginning of February six to eight
army corps, or about 200,000 men.

For months the heavy fighting in the east had centered on other
sections of the immense battle line, running from the Baltic to
the Carpathians. The second general Russian offensive, the great
forward thrust of the Grand Duke Nicholas toward Cracow in the
direction of Berlin, aimed through the center of the German defense,
had been met, and the German counterthrust toward Warsaw had come to
a standstill in the mud of Poland and before the stone-wall defensive
of the Russians on the Bsura and the Rawka. Attacks launched by the
Russians against the East Prussian frontier, centering at Lyck,
in January, 1915, seemed to forebode a fresh Russian offensive
intended to sweep back the German armies in this section whose
position on the Russian right wing was a continual threat to the
communications of the Russian commander in chief.

The Germans, disposing of comparatively weak