The Carpathians were therefore the key to the future of the war and history of south-eastern Europe. The Russians had in the autumn established a solid control of the Galician outlets from the mountain passes, but had made no serious attempt to achieve the far more difficult task of securing command of the foothills south of the range, which alone would enable them to conquer the plains of Hungary. For a mountain pass is like a river bridge-head; one may often possess it without being able to debouch. The Austrians experienced that difficulty in their winter offensive against the Russian flank in Galicia. They made little progress against Brussilov at the Dukla and Lupkow passes, but farther east they seized most of the mountain routes, and Alexeiev was pressed back in Bukovina. Their centre under Linsingen was, however, held up by the Russians at Hill 992 near Kosziowa, and all efforts to dislodge the defenders failed. This defence saved Galicia for the time and prevented the relief of Przemysl, which otherwise would have been certain. For the Austrian right succeeded late in February in recovering Czernowitz, Kolomea, and on 3 March, Stanislau. Reinforcements, however, now reached the Russians; Stanislau was recaptured, the Austrians lost much of what they had gained, and on the 22nd Przemysl weakly surrendered. Its fame as a fortress had been enhanced by its five months' siege since October, but it did not redound to the credit of its defenders. They were superior in numbers to the besiegers, were amply provisioned, and well supplied with heavy artillery and all the munitions of war. Every sort of blunder seems to have been committed by the commander, who apparently regarded the siege as a relief from more arduous work in the field, and capitulated because the repulse of the rescuing expedition foreboded an increase of inconvenience.