With winter's arrival, the German-Austro-Hungarian forces concluded their eastern campaign. After seizing more than half of Ukraine, logistical constraints forced them to halt their eastward advance and turn their eyes toward the southern front.
How could Ferdinand's major moves in Romania possibly be kept from the Alliance? They had the Romanian government-in-exile, after all. Getting intelligence from Romania was hardly difficult.
Falkenhayn had originally planned to turn west after the Eastern Front campaign ended, crush the French in one stroke, and bring this brutal war to an end.
But Bulgaria's continual troop deployments into Romania drew the Austro-Hungarian Empire's attention. In just a few months, it had assembled an army of over a million men, and that number was still growing. Conrad was no fool; he naturally knew they were coming for them, and immediately asked Germany for assistance.
The border between Bulgaria and the Austro-Hungarian Empire was now very long. Bosnia and Herzegovina was relatively manageable, as it was mostly mountainous terrain, making a major war there unlikely.
But the other regions were troublesome. Around Belgrade, for instance, Bulgaria's spearhead was already threatening the Great Hungarian Plain, forcing the Austro-Hungarian Empire to deploy heavy forces for defense.
Transylvania had fallen after the defeat in the winter campaign earlier that year. Now the Kingdom of Hungary lay exposed beneath Bulgaria's advancing blade.
And now Bulgaria was massing heavy forces in Romania. If the Alliance's main force left on one foot and Bulgaria attacked on the next, the Kingdom of Hungary would be unable to hold them off.
Having endured two major wars in a single year, the Austro-Hungarian Empire was now exhausted to the bone. It no longer had the strength to take on Bulgaria alone in a showdown.
The disastrous winter campaign at the beginning of the year had