For a while it seemed as if the Serbians would actually batter their way through. One Serbian regiment charged seven times and each time captured three guns, only to have them wrested out of its hands again. Once the Bulgarians' center was pierced by a tremendous effort on the part of the Shumadians and the Morava troops. The Bulgarians sagged back, and some broke and fled. But again reserves came on the scene, whereas the Serbians were, every last man of them, on the front line of the fighting. Fresh forces of Bulgarians, being shipped up from Uskub by rail, were constantly arriving on the field, and in the end they were enough to turn the balance. For three days the battle had raged, one continuous series of sharp, hand-to-hand encounters, by night as well as by day. But finally, on November 15, 1915, the Serbians had reached the limit of their strength; the battle was going against them. And then they retired from the pass by way of the Jatzovitza Hills toward Prisrend. Thus the plans of the Serbians to cut their path south to their Allies on the Greek frontier were defeated, and they were forced back into the north again. The effect of the collapse of this effort was immediately seen in the withdrawal from Mitrovitza of the Serbian staff, such members of the Serbian Government as had remained there and the diplomatic representatives of the Entente nations. The Bulgarians had been perfectly well aware of the plans that lay behind the tremendous effort made by the Serbians at Katshanik Pass and they had sought to forestall part of it by attacking Kalkandelen, a point which had been taken and retaken more than once. On November 15, 1915, they took it again, and finally, driving the small Serbian force that had occupied it before them, they took Gostivar on the following day, the Serbians retiring to Kichivo, on the road to Monastir. On about the same day, or a little later, Boyadjieff, after a stiff fight, stormed the heights near Gilan, northwest of Kutshanik Pass, and, after occupying Gilan itself, advanced toward Pristina, reaching its vicinity by November 22, 1915. The invaders had succeeded in their main object, which was to round up and if possible corner the main Serbian forces; they were now rolled back on to the great Kossovo Plain, where they were united, but considerably confused and hampered by the vast crowds of fugitives fleeing from all parts of the north, center and east of the country. Near Mitrovitza, on the north of the plain, near Pristina on the east of it, and at Katshanik at its southern extremity, the Austro-Germans and the Bulgarians had, by the beginning of the fourth week of November, 1915, absolutely rounded up and hemmed in all the larger forces of the Serbians. Here they must either surrender, engage in one last desperate battle that meant certain destruction, or retire backward into the mountains of Montenegro and Albania, which by this time were covered with deep snow.