It was obvious that, in spite of the fact that they had assisted in a successful invasion of Serbia, the Austrians, now that they were by themselves again, were not so confident of overcoming even the Montenegrins that they could afford to undertake the campaign impulsively, for during the whole month of December, 1915, they did not press the campaign on the Montenegrin front. During this period and the first week of January, 1916, they were satisfied with more or less holding their lines, though they did advance some distance on the eastern, or Sanjak, front, capturing Plevlie, Ipek, and Bielopolie. But, as an offset to this success, the Montenegrins scored at least one victory of considerable magnitude. On December 1, 1915, the Montenegrin forces operating in southeastern Bosnia defeated the Austrians near Foca, on the Drina, seven miles across the Drina, forcing the enemy to retreat along the river toward Gorazda. A few days later the Austrians retaliated by sending an aeroplane flying over Cettinje, which dropped a number of bombs on that small city. Other aeroplanes, flying over the Montenegrin encampments, dropped circulars stating that all Serbia had been conquered, and if Montenegro made any further resistance, she would suffer the same fate. Toward the end of the month the Austrians began a heavy bombardment of Mount Lovcen and launched a strong infantry attack against it, but were repelled with considerable losses. On December 23, 1915, the Montenegrin Government reported having inflicted a reverse on the Austrians advancing from the east. The Austrians bombarded violently in the Mojkovac sector, then attacked Touriak, in the direction of Rozai-Berane, but were thrown back. At Berane the Montenegrins assumed the offensive for a brief space, and at Bielo they drove the enemy troops back as far as Ivania. However, these were all minor operations and the successes of the Montenegrins were not of a permanent nature. Apparently the Austrians were all this time strengthening their lines and arranging their forces for the general offensive, which they were ready to begin early in January, 1916. On January 6, 1916, Koevess began decisive operations with a series of violent attacks on the eastern front, on the Rivers Tara, Lim, and Ibar, while at the same time the warships in the Gulf of Cattaro opened a terrific fire on Mount Lovcen.