In Macedonia, Todoroff, though his force was much smaller, was having comparatively easy work. A large part of the vital railroad line passed through this section and it was Todoroff's first aim to throw himself astride of it, thus effectually breaking off communication between the vanguard of the French army and the Serbians. It was this portion of the country that the Greeks would have defended, had they joined the Allies. The first thing that Todoroff did was to detach a strong force from his main body, with which he struck at the railroad between Vranya and Zibeftcha and succeeded in cutting it. The detachment of the Southern Morava was driven back at the first encounter and on October 17, 1915, the Bulgarians entered Vranya. On the same day the main body of the Bulgarians advanced down the slopes from Kustendil and took Egri Palanka, on the road toward Kumanova and Uskub. Farther south they penetrated the Valley of the Bregalnitza, the scene of the Bulgarian defeat in the Second Balkan War, where they captured the important strategic point, Sultan Tepe, and the town of Katshana, taking twelve field pieces. Passing rapidly on through Ishtip, they occupied that part of Veles lying east of the Vardar River, where, on October 20, 1915, they again cut the railroad line and so made any further advance on the part of the French almost impossible. The next day the Bulgarians captured Kumanova and then, on the day following, drove the Serbians on through Uskub. The Serbians retired fighting to Katshanik Pass, north of Uskub, where they made a stand that became one of the notable achievements, on their part, of the whole campaign. For by the defense of this pass they made the Bulgarian effort to cut Serbia in two for some time fruitless. CHAPTER XXXIII THE TEUTONIC INVASION ROLLS ON Meanwhile, Bulgaria having plunged into the fighting, the Teutonic allies in the north resumed their efforts to advance southward. But for some time they had all they could do to maintain themselves on the banks of the rivers. Before them rose the rock-ribbed hills skirting the mountains of the interior, and along these hills the Serbians had, during the previous ten months, built up line after line of strong intrenchments, one behind the other. To carry one line was only to gain a few hundred yards of territory. Just as soon as Koevess felt his hold on Belgrade secure, he began an attack on the heights to the south. After three days of intense bombardment he succeeded in taking Mount Avala, an eminence some 1,600 feet in height and ten miles from the city. On the same day, October 18, 1915, Obrenovatz fell into his hands, and Shabatz three days later. However, these two places were still only on the banks of the river.