But this was just the alternative which the Austro-Germans and the Bulgarians were determined to deny them. The Serbian forces still numbered somewhere around 200,000; this body, combined with the allied troops, who would presently be numbering another 100,000, would form a military force, its rear protected by the British and French ships, which the Teutons and Bulgarians would never dare to attack, even though the Greeks still continued neutral. Moreover, there was no doubt that the Greeks would interfere should the Bulgars cross their frontier. This force, then, would continue a constant threat to the lines of communication and transportation which had just been opened up between the Central Powers and Turkey, and along which they would soon be sending large quantities of war munitions to the Turkish forces at Gallipoli. At any moment the enemy at Saloniki might strike, and to guard against such a possibility, the Austro-Germans would have to maintain larger forces along the railroad than they could spare. At all costs the Serbians must be prevented from joining the Allies. And this was the object of the powerful effort made by the Bulgarians to hurl their forces through the gap between Sarrail and the Serbians in the Babuna Pass. However, the Serbians decided on a determined effort to break through the net that was being drawn around them. This meant, first of all, that the Katshanik Pass, which in the second week of November, 1915, was still in the hands of the Serbians but was being attacked from the south by the Bulgarians, had to be first cleared of the enemy, who must then be driven out of Uskub, whence the Serbians would then be able to force their way west to Tetovo, and then south by the main highway through Gostivar and Kitchevo, to Monastir. Once at Monastir the road would be comparatively easy to Saloniki, by way of the short branch of railroad whose terminus was at Monastir. In the effort to carry out this plan one of the most desperate battles of the whole Serbian campaign was fought, quite as bloody and as heroic as any of the large engagements that were fought in the beginning of the invasion. It failed, but it was a failure of which no army need to have been ashamed.