When Grodek fell, Brussilov's soldiers had been marching and fighting without pause for longer than three weeks. The feats of endurance they had performed were extraordinary but without delay they pursued the Austrians from Grodek with the same alertness that they had shown in following them from Halicz.
In the meantime, as we have noted, Rawa-Russka had been taken. Like Brussilov, Russky was not inclined to give an enemy he had bested any chance to recuperate, and while Brussilov was pursuing the Austrian right from Grodek to Chyrow on the south of Przemysl, Russky was following up his success with equal vigor, driving toward Sieniawa the shattered forces which had opposed him.
Sieniawa was occupied on September 18, 1914, the same day that Brussilov took Sambor. Jaroslav was captured by assault on September 21. There was hard fighting on the way there, around Javorow, fifteen miles east of Przemysl, where the Russians claimed to have taken 5,000 prisoners and thirty guns. In such wise was Przemysl cut off on the north, east, and south. Behind its defenses, what was left of Von Auffenberg's army took refuge.
The Austrians also had met with reverses where Dankl's army had been falling back before the troops of Generals Ewarts and Plehve. It has been shown that the continuity of the Austrian defenses had not been effective in the region northwest of Rawa-Russka, though it extended beyond the frontier between Tomaszow and Tarnograd. After the conflict at Tomaszow, the line of the Archduke Joseph Ferdinand above Rawa-Russka to that place had been bent back on the Rawa-Russka-Jaroslav railroad, while the main body of Dankl's troops fell back on the line of the San.
Never was the Russian pressure on its rear relaxed. The pressure was especially strong from the Russian right which had fought the battle of Krasnik, after clearing the Opolie-Truobin district. The larger portion of the Austrian troops crossed the San near its junction with the Vistula. Probably they hoped that while they might place themselves, on the other side, in touch with the Austrian railroads, the river would be a barrier behind them against the Russians.
It appears that General Dankl, anticipating the necessity of falling back across the San, had been sending his transports back in advance of his retreat, almost from the time the retreat began. In fact, some of the transport trains had been sighted and subjected to shell fire as early as September 9, 1914, from the left bank of the Vistula. Not until September 12 did the army itself reach the banks of the San.
Two heavy rear guards, to north and east, were left to hold back the oncoming Russians, while the main body and the baggage were crossing the river on September 12. The Vistula protected the left of one of these rear guards, the San protected the right of the other. Thus the two formed an arch between the two streams.
Marshy ground made difficult the attack on their front, but, nevertheless, they seem to have been unable to prevent the Russians from piercing the screen before the crossing of the river had been completed. There was great slaughter. The Russians claimed that they took 30,000 prisoners. The artillery of the Russians was highly effective in shelling the bridges while the Austrians were passing over them in solid masses. Beside the large number of those killed by shell fire many were reported to have been forced into the water and to have drowned.
Neither was there respite for the Austrians on the other side of the river, although, in theory, the forcing of the passage of the San by an invading army was considered an impossible task. Enormous sums had been spent by the Austrians in an attempt to make it impregnable.
Along the upper or southern part of its extent it was protected by the powerful position of Przemysl and by Jaroslav. From there a light railroad, which had been built solely for strategic purposes, ran parallel and close to its left bank almost to the point where it joined with the Vistula.