After the Battle of Drina, the Serbian army retreated to the right bank of the Kolubara River. The Serbian Army had 250,000 poorly equipped soldiers, the Austro-Hungarians had a well-equipped force of 450,000 men. On 16 November 1914, the Austro-Hungarian Balkan Army group (5th and 6th Army), commanded by General Oskar Potiorek, launched an attack across the river. Potiorek's goal was to gain control over the railroad that led from Obrenovac to Valjevo and to use it for supplying his troops instead of using muddy roads in Mačva. The 5th Army, which held the northern part of the front, captured the town of Lazarevac which was held by the Serbian 2nd Army. In the south, the 15th and 16th Corps of the 6th Army attacked the 1st Serbian Army, captured Mount Maljen on 24 November, and put the Se