d
an official statement that there were no German or Austrian officers
in Sofia and that Bulgaria had no intention of breaking her
neutrality. Meanwhile came reports through Greece stating that
Bulgarian troops were being massed up against the Serbian frontier. As
subsequent events soon proved, Bulgaria was determined to hide her
real purpose to the last moment; not until she actually made her first
attack did she cease denying her hostile intentions.

That Bulgaria was acting in cooperation with the Teutonic allies was
obvious, for already the Serbians had observed that great forces were
being mobilized across the rivers, along her northern and northwestern
frontiers, along the banks of the Danube, the Save, and the Drina.

What did not develop so soon was the fact that this new invasion was
to be under the leadership of the German General von Mackensen, and
that the invaders were to consist in large part of German regiments.
During the summer Mackensen had been engaged in directing a strong
Austro-German offensive against the Russians, with conspicuous
success. For weeks after he had left this front and was busy
organizing a similar offensive against the Serbians, the German
official dispatches continued to associate his name with actions on
the Russian front that the preparations in the south might continue
secret as long as possible.

Not long after the first Austro-German guns began hurling their shells
across the Danube, against the Serbian position at Semendria, the
Serbians learned of the disposition and the resources of the enemy.
The troops under Mackensen were divided into two armies, each in close
contact with the other. One of these wings was under the command of a
German, General von Gallwitz, who had distinguished himself against
the Russians a short time previously. The men under him were entirely
Germans. The other army was under the command of an Austrian, General
von Koevess von Koevesshaza. His men were both German and Austrian, the
latter predominating.

The army under Gallwitz extended from Orsova, near the Rumanian
frontier, along the Danube westward to a point opposite Semendria.
Here his right flank joined Koevess's line, which extended up past
Belgrade, along the Save and part way up the Drina. The rest of the
frontier up the Drina was covered by a smaller Austrian army.

Altogether, the Austro-German armies comprised at least 300,000 men.
The Austrians were picked troops, for it was only