The Defeat of Serbia and Rumania
Austria-Hungary declared war on Serbia on 28 July 1914, the first time that war was declared by telegraph. On 12 August, Austro-Hungarian forces commanded by Oskar Potiorek invaded northwest Serbia. Serbian forces led by voivod (commanderin-chief) Radomir Putnik responded with spirited counter-attacks, between August and early December 1914, along the rivers Jadar, Drina and Kolubara, forcing the Austro-Hungarians out of Serbia. Belgrade was back in Serbian hands by 15 December 1914. While the victories of 1914 over Austria-Hungary were a huge success for Serbia, she lost 100,000 men in battle, with many more soldiers and civilians dying in a typhus epidemic behind Serbian lines.