The way was prepared by the great ten-days' battle of Meiszagola. The unexpectedly rapid fall of Kovno and Grodno had enabled the Germans to threaten the envelopment of Ewarts' army both on the south and the north, on the Niemen towards Mosty and Lida and farther north towards Vilna. The struggle for Vilna was decided at Meiszagola, a village about fifteen miles north-west of the old Lithuanian capital. It was captured on 12 September, and masses of German cavalry swept round from Vilkomir towards Sventsiany and crossed the Petrograd railway to outflank the retreating Russian troops. The evacuation of Vilna began on the 13th, and two days later the menace from the German cavalry became more apparent. Fresh divisions were apparently brought up from Courland with 140 guns; on the 16th they were at Vidzy and on the 17th at Vileika, nearly seventy miles due east of Vilna and in the rear of the Russians escaping thence. They were thus also close to Molodetchno on the railway along which Ewarts was falling back from Skidel, Mosty, and Lida; and control of that junction would have put two Russian armies at their mercy. Just in time Ruszky was restored to the command of the northern group of Russian armies, and the victor of Rawa Ruska and Prasnysz was not doomed now to break his uniform record of success. The situation was not unlike that at Prasnysz, and it was relieved in a similar way by a Russian counter-offensive from Dvinsk against the flank of the German cavalry. Vidzy was recaptured on the 20th, and farther south the pressure slackened along the Vilna-Vileika railway; Smorgon was retaken by a brilliant bayonet charge on the 21st. The door had been kept from closing on Russian armies seeking to escape from the salient between Lida and Molodetchno, while the Germans were squeezed out of that which they had made to the north. They were driven out of Vileika, and gradually the lines were straightened and stabilized so as to run almost due south from Dvinsk by Postavy, Lake Narotch, and Smorgon. Other factors than Ruszky's brilliant strategy contributed to this dramatic defeat of the final German effort of the campaign to annihilate the Russian forces. The Germans had lost in men and impetus during their long advance. Superb though their organization was, lengthening lines of communication across a country ill-supplied with roads and railways, and the necessity of guarding against a hostile population told upon their armies in the fighting-line. The heaviest blow will spend itself in time against an elusive foe, and the longest arm will find the limit of its reach. The Germans had not planned a march on Moscow, but they had hoped to overrun the Russian armies and occupy the winter quarters of their choice. These were denied them on the Dvina, and they had not secured the coveted Riga-Rovno line.