By the end of 1915, during the second half of World War I, which had started by the Austro-Hungarian Empire's attack on a small Kingdom of Serbia, Serbian people, its army, and the state found themselves in the greatest tribulation in its long history. Serbia is attacked by the combined militaries of Austro-Hungarian Empire, Germany, and Bulgaria. Defending every road, every hill, every creek, during the time when every village, every plato, every crossing was becoming a historical landmark, Serbia, relying on the Allies, moved its people, its government, and its remaining troops to Kosovo--the only unoccupied part of the Serbian territory, but soon had to cross Albania in the hopes of reaching the Allies' ships in the Mediteranian.