A month previously, when the Russians were within a hundred miles of the fortress, it was ill prepared to stand a siege. While they were retiring to the San and advancing again, the Austrians had been busy strengthening its defences by making a wide circle of trenches around the city, and putting big movable guns into them, as the French had done at Verdun.[166] No field army, however, had been placed in these trenches, because it was hoped that Mackensen's new move on Warsaw would be sufficient to cause the Russians to retire again. By the end of the first week in December it was clear that Brussilov and Dmitrieff were not going to be drawn off by any threat in Poland, but were going to leave the defence of Warsaw to the other Russian forces. The Austrians now saw that they must attack the Russians in Galicia, unless they were prepared to see Cracow fall into the hands of the enemy. Two armies were, therefore, launched against the Russians. The first army, which consisted largely of Hungarians, pushed up from the plain to the south through the Carpathian passes in order to sweep Brussilov out of them and then threaten the Russian rear and its lines of communication. Meanwhile a second Austrian army moved from the south-west amongst the foothills of the Carpathians, and struck at the left of the Russians in front of Cracow. The two armies attacked at the same time. On 8th December, while Brussilov was heavily engaged in the mountains, Dmitrieff fought a battle on the outskirts of the city. He held his own well, but he found that the Austrian right was working its way through the higher glens so as to reach the valley of the river Donajetz[167] and threaten his rear, and that at the same time a third force from the direction of the Warta was strongly attacking his right. He was, therefore, obliged to fall back. [Illustration: Position of the Russians in Galicia at Christmas.] Four days later the Austrians succeeded in seizing the broad and easy pass of the Dukla, and were in a position to pour their forces down upon Galicia, and hold up the rear of Dmitrieff's army while the other army strongly attacked it from the west. The position of the Russians was now very dangerous, and another retirement was necessary. Dmitrieff fell back behind the line of the river Donajetz and its tributary the Biala, so as to cover the mouth of the Dukla Pass. His front now curved from the Vistula to the east of its confluence with the Donajetz, Tarnow on the Biala, past Krosno, and almost to the head-waters of the river San. Brussilov continued the line south-eastwards, and covered the northern exits of the Lupkow Pass and the Uzsok Pass.