Battle of Mościska and Lubaczów begins

Early on the morning of 12 June 1915 the artillery of the Austro-Hungarian Fourth Army opened fire on the Russian positions on the eastern bank of the San near Sieniawa. German and Austro-Hungarian infantry crossed the river and the Lubaczówka, which flows into it, and broke into the Russian trenches. Thus began the Battle of Mościska and Lubaczów, the next stage of the Central Powers’ offensive in Galicia after the recapture of Przemyśl. Its objective was Lviv.

The decision to march on Lviv

As late as May the German and Austro-Hungarian commands had assumed that the offensive would stop on the San and the Dniester and that some of the troops would be transferred against Italy. After the fall of Przemyśl on 3 June, however, the chiefs of the general staffs, Erich von Falkenhayn and Franz Conrad von Hötzendorf, decided to keep beating the Russians while they were weakened and short of ammunition. Conrad wanted to strike from Przemyśl straight at the capital of Galicia. Falkenhayn hoped that the loss of Lviv would have a depressing effect on the Russians and bring peace closer, and Conrad that it would keep Romania from moving against the Central Powers.

General August von Mackensen received new German divisions and command of three armies: the German Eleventh and the Austro-Hungarian Second and Fourth. For more than a week he brought up ammunition and prepared the attack. The Eleventh Army was to deliver the main blow on 13 June, and the Fourth Army was to cross the San a day earlier to cover its left flank.

The Russians before the battle

After the loss of Przemyśl the Russian Eighth Army of General Aleksei Brusilov dug in on the hills west of Mościska, and to the north of it the Third Army of General Leonid Lesh on the Lubaczówka and the San. Both armies had been bled white. According to Russian reports cited by the Austrian official history, the South-Western Front lost 412,000 men in May alone. The front commander, General Nikolai Ivanov, reported on 5 June that they had to defend themselves with the utmost tenacity, because the enemy would eventually run out of shells. He withdrew several corps into reserve, three of them to the area of Lubaczów.

The crossing at Sieniawa

At Sieniawa, during the night of 26–27 May, the Russians had pushed the Austrians back across the San in a surprise counter-attack. Now, according to the Encyclopaedia Britannica, the artillery preparation began at 5.40 a.m. The German 119th Infantry Division on the left wing of the Eleventh Army and the German 22nd Division, fighting alongside the Austro-Hungarian XVII Corps, crossed the river in the morning and, despite stiff resistance from the Russian III Caucasian Corps, broke into its positions. Progress was slower for the Austrian 26th Rifle Division opposite Sieniawa itself, where the eastern bank was strongly held. According to the Austrian official history, this caused alarm in the staffs all the way up to the headquarters at Teschen. In the afternoon the crossing succeeded here too, and in the evening the division passed through Sieniawa. The engineers threw two bridges across the San.

On the rest of the front, from the Lubaczówka to Mościska, the day was quieter. The Russians, however, had long expected a great attack. At 4 a.m. the next day several hundred German and Austro-Hungarian guns opened fire along the whole length of the Russian positions.