Sventsiany Breakthrough of 1915

an offensive operation during World War I by the German Tenth Army, under the command of General H. von Eichhorn, against the Russian Tenth Army of the Western Front, under the command of General E. A. Radkevich, from Aug. 26 (Sept. 8) to Sept. 19 (Oct. 2), 1915.

In the Vil’na (Vilnius) Operation of 1915, the Russians halted the German advance in August; in the course of the operation, however, a gap opened to the north of Vil’na between the Russian Tenth and Fifth armies. The German command resolved to exploit the gap and carry out a deep close envelopment of the Russian Tenth Army’s right flank.

On August 27 (September 9), a German cavalry group, under the command of General Gamier and consisting of four cavalry divisions, with two more cavalry divisions added on August 31 (September 13), entered the gap between the Russian front lines and developed an offensive toward Sventsiany (Ŝvenčiónys) and Molodechno, hoping to take the area near Vi-leika, Molodechno, and Smorgon’ and gain the rear of the Russian Tenth Army, the Gamier group was initially successful. It took Vileika on September 1(14), and its main forces advanced as far as the Smorgon’ area, destroying railroad facilities and the Russian Tenth Army’s logistical services.

The Russian Tenth Army withdrew from Vil’na, and the Russian Fifth Army retreated to Dvinsk (Daugavpils). The Russian command quickly transferred several corps from several different armies into the area of the breakthrough, combining these units under the command of the Second Army. On September 3 and 4(16 and 17), the German cavalry was halted on the approaches to Molodechno; lacking infantry support, it had to retreat under Russian pressure. By September 19 (October 2), the Sventsiany Breakthrough had been halted, and the front stabilized on a line stretching from Lake Drisviaty to Lake Naroch’, Smorgon’, and Deliatin. Both sides thereupon shifted to a positional defense.