The Dunajec-San Operation. Reenforced by the Austrian VI. Corps already on the front, and placed in general charge of the Austrian IV. Army as well as of his own, Mackensen was himself subordinated to Conrad's headquarters, though in fact no major decision could be taken without Falkenhayn's agree- ment. On the Nida front the Austrian I. Army, and in the Beskidengebirge the Austrian III. Army, stood on the flanks of the two attack armies, and in case of success would be carried along as supports. On May i (see DUNAJEC-SAN, BATTLES or) Mackensen's artillery preparation began. The scale of artillery and trench-mortar strength hardly higher than that of a quiet sector in France in 1918 was, for the East and for 1915, over- whelming. At night, as a final diversion, an Austrian division crossed the Dunajec a little above its mouth and established two bridge-heads. On May 2 Mackensen's attack was launched be- tween Woynicz on the Dunajec and Malastov (S.-S.E. of Gorlice). The troops of Radko Dimitriev gave ground, fighting stubbornly. By the 6th they had retired with heavy losses beyond the Wisloka; and the Austrian III. Army, taking up the attack in echelon rightward, had regained the Dukla Pass. By the pth Mackensen had forced the Wisloka, Boroevic was at the evacu- ated Lupkow Pass, and even Linsingen's left was advancing. On the nth, on the other flank, the Russian IV. Army evacuated the Nida position, pivoting on Kielce. Operations were fluid, and it was Falkenhayn's and Conrad's problem to maintain them so.
Falkenhayn's intention was to ensure this by making the operation continue as a tactical one, with as little regrouping as possible outside the limits of the battle that was in being. For this reason he rejected a proposal of Conrad to reenforce, at Mackensen's expense, the Pflanzer-Baltin group (now called VII. Army), which by reason of its position might be enabled thereby to reach the rear of the Russian southern wing. He ignored the relief offensives started by his opponent against the front of Pflanzer-Baltin and elsewhere, and he even sought to utilize the attack upon Pflanzer-Baltin as a means of setting in motion the German South Army and the still stable portion of the Carpathian front, E. of the Lupkow Pass. But at first he had no intention that the effort should go in the slightest beyond its tactical limit, which he fixed as the San-Dniester barrier. Conrad agreed. Both leaders were anxious to disengage large forces for use against Serbia or Italy or both.
As foreseen, the rush of the Gorlice offensive came to a stand on the San-Wisznia line. The Grand Duke had, under cover of his relief offensives, collected adequate forces on the III. Army front and was prepared to hold it firmly. By the i4th Mackensen had taken a total of 140,000 prisoners and more than 100 guns, and had reached the line Tarnobrzeg on Vistula (link with Opatowka line)-Nisko on San-Sieniawa (Austrian IV. Army); Sieniawa- Jaroslaw-Radymno (XI. Army); Magiera and Chyrow region (III. Army) ; Stary-Sambor (II. Army). But along the lower San, in the bridge-heads of Jaroslaw and Radymno and the fortress of Przemysl, the Russians were ready to fight again, on the alert, in prepared positions, and had by demolitions of all sorts made the supply problem difficult for the Germans and Austrians. At that date Brussilov's VIII. Army and Shtchcrbachev's XI. on its left were intact; Szurmay's and the left of Linsingen's were only beginning to advance; while Pflanzer-Baltin was on the defensive along the Pruth except at Kolomea where he still held a bridge-head. Moreover, Italy was on the point of declaring war (as she did on the 24th) and Rumania's intentions were impenetrable. On the western front, the French and British had opened their relief offensives of May 9 (battles of Carency and Festubert). The Dardanelles was under military as well as naval attack, and the Turkish and Balkan problems, always obscure, had thereby become acute as well.
Nevertheless, during the fourth week of May, Falkenhayn finally determined to carry on the Galician offensive and even to extend it. It appeared, from Mackensen's reports, that the shortage of munitions on the Russian side, already observed here and there, was general, and that it was possible in consequence to keep the offensive alive till it had secured a decision " suf- ficient for our purposes," in Falkenhayn's own words. Fresh
troops were drawn from the West in spite of the crisis north of Arras. Hindenburg was invited to press the advance of Woyrsch's army group which had already begun on the I2th to move forward on the left of the Austrian I. Army and was in front of Radom by the i6th up to the Vistula below the San confluence. As in the Vistula-San operation of October 1914, the threat of turning the San line by Josefow was thought to be an effective means of weakening it against frontal attack. Ludendorff, how- ever, declared this operation to be impossible, in spite of the offer of fresh divisions his mind was already set upon a more grandiose scheme. Falkenhayn thereupon gave the incoming di- visions (25 from France and 2 from Poland) to Mackensen, and on June 3 that general received instructions to push the XI. and IV. Armies over the San barrier, south of the Tanev, in coopera- tion with an eastern advance of the Austrian II. Army (now comprising what was left of the III. after Boroevic's departure for Italy), which should "finally " beat the enemy still remain- ing south of the Dniester in front of the South and VII. Armies. Hindenburg was merely " to take any chance that offered itself anywhere of profiting by the enemy's shortage of munitions." In sum, then, the scheme was simply a prolongation eastward of the Gorlice-Tarnow effort by means of a fresh engagement of reserves. No new operative idea was involved. But the decision to continue the battle was in itself an operative decision of the first importance, and, in view of the general war situation, a very bold one.
Mackensen meanwhile, partly urged by his own fighting spirit, partly compelled by Russian counter-attacks, had been involved in constant fighting on and for the San line. The Austrian IV. Army was strained to the utmost in holding on to the positions it had gained on the middle San (below Sieniawa) and in front of the link Nisko-Tarnobrzeg (or " San angle position ") which joined Radko Dimitriev's front to that of Evert on the Opatowka. The right of the XI. Army was simi- larly held up by the Russian positions about the Radymno bridge-head, and Przemysl interposed a formidable obstacle between that army and the advancing Puhallo group (the relic of the Austrian III. Army, which included also the German Beskidenkorps). But the left of the XI. Army stormed the Jaroslaw bridge-head and, crossing into the Lubaczowka valley, pressed the right rear at the Radymno bridge-head farther up the San.. On May 24 a general assault carried this line, and the Russian centre, its right still holding the " San angle " position and the San below Sieniawa, fell back to the line of the Wisznia, the Grodek lakes, and the Wereszyca. Practically at the same time, the right of the XI. Army, Puhallo, and the left of the II. Army closed upon Przemysl from the N., W., and S.; after severe fighting the fortress fell on June 3, as described under PRZEMYSL. Farther E., the right of Bohm-Ermolli's and the South Army, advancing in the last ten days of May x reached the line Weliko Bloto (" great marsh ") on the Dniester-E. of Drohobycz-S. of Stryj-Dolina, making connexion at Jasien with the left of the VII. Army, which was holding, still with success, the Pruth line.
The Russians, however, failing as we/e their resources, reacted powerfully. The Grand Duke's instructions were that " for political reasons, it is imperative to hold " the Opatowka-San- Grodek line " at all costs," and he carried them out by a series of heavy counter-strokes. First on the lower San against the Austrian IV. Army, then on the Pruth against Pflanzer Baltin, and lastly against Linsingen on the Stryj front, offensives on a large scale were delivered in the latter half of May and the first week of June. New masses were drawn from an army at Odessa which was to have cooperated in the attack on Constantinople. Even Woyrsch's advance, far away on the Kielce-Radom railway, was opposed by stubborn defence and sharp local counter-attacks. But in the last resort the Grand Duke's forces were inadequate for prolonged defence. The long exposed flank of the northern corridor compelled him to keep fair- ly large forces inactive on the Narew, the Bobr, and the Niemen; and the Lauenstein operation in Courland (described below) made a continual drain on his northern resources. But above
