The Serbians had not yet been driven back on the line along which they had originally intended to make their first stand against the invaders. During the period between the first mobilization and the beginning of the first invasion on August 12, 1914, what are referred to as the Kolubara and Lyg positions had been strongly intrenched. But it had not proven necessary to fall back on these positions; the Austrians had been driven back at once. But now, after the fall of Valievo, the Serbians decided to make no further resistance to the Austrian advance until this line was reached. The Kolubara River itself is not of sufficient width to hold back an advancing army long, but in places its banks rise so high and steep that it serves very much the same purpose as a moat before a castle. In such places comparatively few men could hold back a large number of the enemy. A little south of Lazarevatz the line of intrenchments left the Kolubara and followed the Lyg River, where the country was even more rugged. From the source of the Lyg the Serbians had fortified the Jeljak and Maljen ridges, which control practically all the roads leading to Kragujevatz and, proceeding in a southwesterly direction, they threw up earthworks on the Bukovi, Varda, Jelova, Bukovic, Miloshevatz and Leska Gora ranges, which defended an advance toward the Western Morava Valley. CHAPTER LV PRELIMINARY AUSTRIAN SUCCESSES It was along this line that in November, 1914, the Serbians determined the decisive battle of the campaign should be fought. At Obrenovatz was stationed a strong brigade, known as the "Detachment of Obrenovatz." Further south, at Konatiche, on the Kolubara River, the cavalry division cooperated with the Second Army, which held the line from Volujak to Cooka and the ridges farther to the left. The Third Army occupied the right bank of the Lyg River from Barzilovitza to Ivanovchi. The First Army stretched itself out from Gukoshi to Ruda and along the Jeljak ridges to Maljen. And finally the "Army of Uzitsha," which had fought so brilliantly before in the southern section and penetrated into Bosnia, was assigned the protection of the base at Uzitsha and the Western Morava; it intrenched itself from a point southwest of Yasenovatz, through Prishedo, along the Jelova crests, after which it crossed over to the heights of the Leska Gora to Shanatz. This new line, much shorter than that previously held, enabled the Serbians to contract. Moreover, all the country was favorable to defense. Nowhere was it so screened that an approaching enemy could surprise them. Here, certainly, one defender was equal to two invaders.