The Sventiany Offensive was a military operation mostly undertaken by the 10th German Army against the 10th Russian Army as part of the Eastern Front

Eastern Front (World War I)

The Eastern Front was a theatre of war during World War I in Central and, primarily, Eastern Europe. The term is in contrast to the Western Front. Despite the geographical separation, the events in the two theatres strongly influenced each other...

 during World War I

World War I

World War I , which was predominantly called the World War or the Great War from its occurrence until 1939, and the First World War or World War I thereafter, was a major war centred in Europe that began on 28 July 1914 and lasted until 11 November 1918...

. On September 9, 1915, four German cavalry

Cavalry

Cavalry or horsemen were soldiers or warriors who fought mounted on horseback. Cavalry were historically the third oldest and the most mobile of the combat arms...

 division

Division (military)

A division is a large military unit or formation usually consisting of between 10,000 and 20,000 soldiers. In most armies, a division is composed of several regiments or brigades, and in turn several divisions typically make up a corps...

s, enforced from September 13 by two others, filled the gap in the Russian front and deployed an attack to gain the rear of 10th Russian army. On September 9 the Germans broke the Russian defence and six cavalry divisions were thrown into breach. Later however the German onslaught, devoid of infantry and artillery support, weakened and on September 15–16 was finally stopped by the newly formed 2nd Russian army. On October 2 the Sventiany breach was eliminated.