After several years of smaller involvement of Poland in the war against Turkey, Sobieski decided again to turn to Austria and the Holy League. However, the condition for full cooperation with the Hapsburg ally was solving the issue of the Danube Duchy. The emperor perceived both lands as his possession, granting Sobieski and the Republic only Podolia and Kamianets. Leopold I would have preferred Poland to settle its borders on Dniester, not Danube, as Sobieski had planned. The Emperors attitude to the Danube issue changed only after the mission of the cardinal Michał Radziejowski in Vienna in November 1690 and Austria's problems in competing with the King of France Louis XIV on the river Rhine. Finally Leopold I admitted Sobieski the right to occupy Moldavia, but granted himself Wallachia as future conquer. Sobieski was satisfied with such outcome and with the support of the Seym, began planning the Moldavian campaign for 1691.
In April 1691 on the Senate Council, the king granted himself the ratification of another campaign to Moldavia. During another council in August, a more detailed plan of action towards Danube was established. The army of 30 thousand soldiers under the personal leadership of Jan III would enter Moldavia, conquer it, and then begin cooperation with the Emperor's army towards Hungary and Transylvania. This time the Polish monarch was much more cautious than in 1686. His plan also assumed conquering Soroka, in order to eliminate the possibility of transporting food and ammunition to Kamianets. In case of failure in Moldavia, Sobieski wanted to withdraw from the 1691 campaign with at least some achievement, not entirely defeated, as it happened 5 years earlier.
In the last days of August 1691 the second royal campaign into Moldavian Hospodar Landwas undertaken. Initially it was very successful. Having crossed the river Prut near Sniatyn the army marched through Linkowice and Bojan to the village of Handrykowce. It was there, that the presence of Tatar troops was first noticed, but they avoided provocation. Therefore the army moved on towards the river of Pereryta, where on 12th-13th of September it clashed with the Orda. Owing to heavy artillery firing, infantry and dragoons, the Tatars were defeated. Subsequently the river Prut was crossed and the army headed for Iasi. Sobieski still hoped that hospodar Kantemir will pass to Polish side. However, he left his capital and joined the Tatar camp, as soon as he found out about Polish forces closing in. The inveterate optimist Sobieski was cheated again by the treacherous hospodar. This incident, however, did not cause the change of king's plans. Having learned about the victory of emperor's forces in the battle of Slankamen and that the Castellan of Chelm Stanislaw Druszkiewicz had occupied Soroka, Sobieski decided to march on towards Iasi, hoping that Tatar-Moldavian forces blocking the access to the town are weak and will be easily defeated or not indulge in the fight at all.
The Tatars indeed tried to avoid clashes with the army of the Republic, but there was a much more difficult enemy to battle – hunger. At the end of September the food supply for the royal army began to run out. Thus the march to the Moldavian capital was abandoned and decision was made to turn towards Roman. Food stock was believed to reach the town. Unfortunately the town was no good for setting up a fortified camp, thus an attempt was made to conquer the town of Neamt. 'Assisted' by the Tatars and indulging in minor battles, on the 13th October the army of Jan III reached Neamt. The town surrendered on the following day due to artillery fire deftly carried out by Marcin Kątski. Having Neamt manned and supplied with food, Sobieski headed for Danube. This time, however, the army opted for withdrawal to the Republic, to which the king finally had to agree. After a repose in Suczawa the army marched towards Śniatyń, where at the end of October 1691 the border of the Republic was crossed.
Another Moldavian campaign was to end up in failure of the king's plans. Although Soroka and Neamt had been conquered, but it could not be acknowledged as a spectacular success of the 1691 campaign. It was the last war campaign under the personal leadership of Jan III Sobieski. The ailing monarch never put on an armour or mounted a horse again. Neither did he lead the Republic forces to glorious victories, which he missed so much in his last years.
Sad was the end of military plans of Jan III – the victor of Vienna and Khotyn great battles. With all certainty it can be concluded that the failure of Moldavian campaigns was partly due to difficult situation inside the Republic, where the opposition party grew into strength. Its representatives successfully blocked the king's proposals of structural and military reforms, and additional they pursued their own foreign policy, contradictory to the plans of the royal court. However, not only internal issues contributed to the failures in the war against the Ottoman Empire. The attitude of the Republic's main ally from the Holy League – the Emperor – left a lot to wish for. On numerous occasions, he reject Sobieski's brave and well calculated plans of Hapsburg and Polish army cooperation. He never decided to take risk in battles against Turkey, fearing to a large measure, that in case of victory, he would have to share the loot with the Polish Emperor. This largely contributed to mere effects of several Polish campaigns into Danubian Duchy. The reluctance to acknowledge the rights of the Republic to occupy Moldavia and Wallachia meant that Sobieski could not count on the support of Hapsburg military forces in key moments of his campaigns.
It can also be speculated whether the king's dynastic plans did not influence too strongly the course of action in the Turkish war, or whether it would be wiser to focus military efforts on liberating Kamianets from and dislodging the Turks from Podolia. However, as several attempts proved, conquering the fortress of Kamieniec was not an easy task. From present perspective, perhaps we should agree with Sobieski, who claimed that conquering Moldavia and defeating Budjak Tatars would cut The Kamianets crew from supplies and, consequently their surrender. The argument can solved by an in-depth source analysis.
