When the Great War broke out in July, 1914, this Bulgarian activity in Serb Macedonia grew more intense.  Thus it was that when the Austrians attacked the Serbians on their front the Serbians had still to detach enough of their forces to guard the Serbo-Bulgar border to prevent the crossing into Serb Macedonia of Bulgar bands.  And added to this was the danger from Bulgaria herself.  The Serbians knew that the opportune moment had only to come and Bulgaria, too, would hurl herself on the Serbian eastern flank.  Thus another large percentage of the Serbian fighting forces had also to be stationed along the Bulgarian frontier to guard against possible attack from that quarter.

Offsetting these handicaps, however, and more than equalizing them, was the moral strength of the Serbian fighting units.  They had just emerged through two victorious wars; they had triumphed so completely that there was small wonder if the Serbian farmers had come to believe themselves invincible and their leaders infallible.  Practically every man in the Serbian army was a seasoned veteran; he had had not only his baptism of fire, but he had been through some of the bloodiest battles of modern times.  He had got over his first fright; he was in that state of mind where danger and bloodshed no longer inspired either fear or horror.  And even the warlike savage trembles on entering his first battle.  Finally, he was now defending his country, his home, his very fireside and his family against foreign invasion.  And it is generally admitted that a man fighting in that situation is equal to two invaders, all other things being equal.

The Serb army opposing the Austrian invasions was composed of ten divisions of the First Ban and five divisions of the Second Ban.  Five of the divisions of the First Ban and the five of the Second came from the kingdom as it was prior to the two Balkan wars, but the second five divisions of the First Ban were new creations recruited from Serb Macedonia.

The principles on which the organization of the Serbian army was based were very simple.  The former kingdom was divided into five territorial divisional districts—­Nish, Valievo, Belgrade, Kragujevatz, and Zaitchar.  Each of these territorial divisional districts was subdivided into four regimental recruiting districts, each of which provided one infantry regiment of four battalions and one depot battalion.  The battalion numbered about a thousand men, so that the war strength of the divisional infantry amounted to about 16,000 men.  Attached to each division was a regiment of artillery, consisting of three groups of three 6-gun batteries; in all, 54 guns.  The divisional cavalry, existing only in war time, consisted of a regiment of four squadrons, from men and horses previously registered.  To each division was also attached its own technical and administrative units, engineers, and supply column, and its total strength amounted to 23,000 officers and men of first-line troops.