Dee ihe na-esote paragraf a - Mgbe mmeri nke ndị agha Serbia na Agha nke Kolubara
na Disemba 1914, ndị agha Serbia kwụsịtụrụ ruo ná mmalite oge mgbụsị akwụkwọ nke 1915. N'okpuru iwu nke Field Marshal August von Mackensen, ndị agha Austro-Hungarian Balkan Army, ndị agha German nke 11 na osimiri mmiri na Danube na Sava malitere mwakpo na 6 Ọktọba 1915, mwakpo kachasị ukwuu megide Serbia. Ka ọ na-erule Septemba 1915, n'agbanyeghị oke ịchụ àjà nke ndị agha Serbia, ndị agha Austro-Hungarian Balkan, mgbe ha gafere osimiri Sava na Drina na ndị agha nke 11 nke German mgbe ha gafesịrị Danube, weghaara Belgrade, Smederevo, Požarevac na Golubac, na-eke akwa akwa akwa n'ebe ndịda nke osimiri Sava na Danube. Nke a, jikọtara ya na ndị agha Bulgaria gara nke ọma na Morava, Ovče Pole na Kosovo manyere ndị agha Serbia ịlaghachi na Gris na-anọpụ iche. France na Britain bufere ndị agha si na Gallipoli Campaign gaa Greek Macedonia. Ya mere e guzobere ihu ndị Masedonia na mbọ iji kwado ndị agha Serbia fọdụrụnụ iji merie Vardar Macedonia.