On May 4, 1915, the Russians began to evacuate the positions they held south of the range when Von Mackensen's extreme right approached Krempna. Forging along at high speed the Germans and Austrians occupied the towns of Dukla and Tylava, and arrived at Rymanow--still farther east--on the following day. The town of Dukla lies some fifteen miles due north of the Galician debouchment of the pass of that name, and Rymanow is about another fifteen miles east of that. Hence the German strategic plan was to draw a barrier line across the north of the Carpathians and hem the Russians in between that barrier and the Austro-Hungarian armies of Boehm-Ermolli and Von Bojna. It must distinctly be borne in mind that these two forces are also north of the passes: that of Von Bojna being stationed at the elbow where the Germanic line turned from the Carpathians almost due north along the Dunajec-Biala front, or across the neck of our hypothetical jar. The Dukla and Lupkow passes were still in Russian hands; these were the only two that the Germanic offensives of January, February, and March, 1915, had failed to capture; all the others, from Rostoki eastward, were held by the Austrians and Germans. It was through the Dukla and Lupkow that the Russians obtained their foothold in northern Hungary, and it was the only way open to them now to get back again. Around the Laborcza district stood the Seventh Austro-Hungarian Army Corps under the command of the Archduke Joseph, who now began to harass them, aided by the German "Beskid Corps" under General von Marwitz. This was the only section in the range where the Russians held both sides. Boehm-Ermolli had forced the Rostoki and Uzsok, but hitherto had been unable to get very far from their northern exits--not beyond Baligrod. During the fighting on the Dunajec these three armies merely marked time; it was their object to keep the Russians in Hungary and in the two passes until Von Mackensen had thrown the right of his "phalanx" across their only avenue of escape. That time was now rapidly approaching, and Von Bojna was gradually squeezing Brussilov from the west, while Boehm-Ermolli was following from the east and south. It appears that the commanders of the Twelfth Russian Army Corps and the Third Russian Army, which stood on Hungarian soil from Zboro to Nagy Polena, did not grasp the full significance to them of the Dunajec catastrophe.