It is unnecessary to describe the events which succeeded the fall of Warsaw in great detail.  There was a constant succession of German victories and Russian defeats, but never one of the Russian armies enveloped or destroyed.  Back they went, day after day, always fighting; each great Russian fortress resisted until it saw itself in danger, and then safely withdrew its troops.  Kovno fell and Novogeorgievsk, and Ivangorad, then Ossowietz was abandoned, and Brest-Litovsk and Grodno.  On September 5th the Emperor of Russia the following order: 

Today I have taken supreme command of all the forces of the sea and land armies operating in the theater of war.  With firm faith in the clemency of God, with unshakable assurance in final victory, we shall fulfil our sacred duty to defend our country to the last.  We will not dishonor the Russian land.

The Grand Duke Nicholas was made Viceroy of the Caucasus, a post which took him out of the main theater of fighting but gave him a great field for fresh military activity.  He had been bearing a heavy burden, and had shown himself to be a great commander.  He had outmaneuvered von Hindenberg again and again, and though finally the Russian armies under his command had been driven back, the retreat itself was a proof of his military ability, not only in its conception, but in the way in which it was done.

The Emperor chose General Alexieff as his Chief of General Staff.  He was the ablest of the great generals who had been leading the Russian army.  With this change in command a new spirit seemed to come over Russia.  The German advance, however, was not yet completely checked.  It was approaching Vilna.

The fighting around Vilna was the bitterest in the whole long retreat.  On the 18th of September it fell, but the Russian troops were safely removed and the Russian resistance had become strong.  Munitions were pouring into the new Russian army.  The news from the battle-front began to show improvement.  On September 8th General Brussilov, further in the south, had attacked the Germans in front of Tarnopol, and defeated them with heavy loss.  More than seventeen thousand men were captured with much artillery.  Soon the news came of other advances.  Dubno was retaken and Lutsk.

The end of September saw the German advance definitely checked.  The Russian forces were now extended in a line from Riga on the north, along the river Dvina, down to Dvinsk.  Then turning to the east along the river, it again turned south and so on down east of the Pripet Marshes, it followed an almost straight line to the southern frontier.  Its two strongest points were Riga, on the Gulf of Riga, which lay under the protection of the guns of the fleet, and Dvinsk, through which ran the great Petrograd Railway line.  Against these two points von Hindenburg directed his attack.  And now, for the first time in many months, he met with complete failure.  The German fleet attempted to assist him on the Gulf of Riga, but was defeated by the Russian Baltic fleet with heavy losses.  A bombardment turned out a failure and the German armies were compelled to retire.