In Rumania, west of the river, continuous and at times heavy fighting continued, sometimes assuming almost the proportions of pitched battles. During the last week of the month Mackensen apparently realized the hopelessness, for the present at least, of driving the enemy out of Dobrudja, and shifted some of his forces over to the west bank of the river. The Russians had retired behind the Rimnik River, a small stream which is about twenty-five miles north of the Buzeu and parallel to it. On January 1, 1917, the Germans announced that the Russians had been forced back against the bridgehead at Braila and that in the Dobrudja they had advanced beyond Matchin. On the 5th, Braila, the most important city left to the Rumanians, fell into the hands of Mackensen, and at the same time the last of the Russians retired from the northern tip of Dobrudja. This was the heaviest blow that had fallen since the capture of Bucharest, and from a military point of view was even more serious. Once driven across the broad waters of the Danube mouth, the Russians and the Rumanians could not recross in the future except in very strong force and with great losses. At the same time it was now possible for Mackensen to reduce his forces in Dobrudja to a minimum and reenforce the troops operating over in Rumania proper. During the rest of the month the fighting continued up and down the line with unabated vigor, though without any sensational results. The Germans were now hammering at the main line of the Russian defense and could not expect any large gains. The defeat of the Rumanians had been, after all, only the driving back of a salient. But in general the fighting during the latter half of January, 1917, seemed to favor the Teutons.