The Morava Offensive Operation (Bulgarian: Моравска настъпателна операция), (Serbian: Битка на Морави) was undertaken by the Bulgarian First Army between 14 October 1915 and 9 November 1915, as part of the strategic offensive operation of Army Group Mackensen against Serbia in 1915. Under the command of Lieutenant General Kliment Boyadzhiev, the Bulgarians seized the fortified areas of Pirot, Niš and the valley of the river Morava. As a result, the Serbian forces were compelled to retreat towards Kosovo and Metohija.
Due to the harsh weather, the defenders' strong resistance and the rough terrain, early Bulgarian advance was slow. But because the defenders were severely outnumbered, the Bulgarians broke through near Pirot in 10 days, and the Serbs retreated to the Timok.
The battle continued for 27 days, and the Bulgarians penetrated up to 90 km deep into Serbia's territory. The Serbs lost 6,000 men, 60 guns, and a large amount of military equipment.
Fetching the article from Wikipedia…
Text from the Wikipedia article “Morava Offensive”, available under CC BY-SA 4.0.