Morava Offensive

On October 14th 1915, Bulgaria joined the war on the side of the Central Powers, and on that same day also joined them in launching offensives against Serbia. The Bulgarian effort itself was centered around the Morava River Valley, with a key Serbian defense in the region being the town of Pirot and its 14th century castle. The Serbians may be outnumbered, but if they fail here they risk losing their entire nation to the invaders.