The incursion of Jan Zamoyski, the Grand Crown Hetman of Poland, has been called back almost as soon as his army encircled Kostrzyn - for, seemingly to the Pomeranians, no reason. It didn't matter, of course, what the reason was, for the result was obvious: the Poles 'just' pillaged the countryside of Neumark, but were unable to take the main cities of the province. Situation was the same in Hinterpommern, where a few thousand enemy troops were stationed, blockading the main city - Stargard. By December 15, 1583 Bogusław Gryfita's army had taken hold of Kulmerland, and with the main cities in Mazowsze already in Pomeranian hands, he decided to cross the river Wisła (Vistula) and assault Inowrocław, Dobrzyń and Brześć - the main cities of the Kujawy region. Bogusław knew that taking them would deal quite a blow to the Polish economy. Inowrocław especially, was one of the cities belonging directly to the Crown, its riches coming from the existence of a salt-works and a large market, present there since as long ago as the 12th century.
In the beginning of the year 1584, the reason for calling back Zamoyski's troops had become clear to the Pomeranian command: he was to return to Mazowsze, in order to retake it from Pomeranian troops. At the same time, two smaller forces of about 10'000 men each were to distract Bogusław Gryfita, if not to repel him from Kujawy - in which they succeeded, coming to the aid of Inowrocław at the time of a general Pomeranian assault on its walls. Bogusław's forces were defeated and forced to retreat to Mazowsze - as Kulmerland had been cut off by the rear guard of the victorious Poles. Bogusław was hoping to be able to repeat the Polish manoeuvre and defeat Zamoyski during his assault of Płock, but the city fell to his army two days before the arrival of the Pomeranian one, which was forced to once again retreat - this time toward Kulmerland. Just after regrouping there, Bogusław directed his force back into Kujawy, where his troops were soon approached by a Polish army of a similar size to their own - circa 18'000.
The battle was a victory. Bogusław ordered his force to attack another, this time smaller, Polish army, awaiting in Wielkopolska, which was quickly routed. There, he lay siege to Gniezno, trying to assault the city almost immediately. This proved to be a bad idea, as the assault had failed, and a Polish army of just 8'000 men, led again by Zamoyski, intercepted the Pomeranian one soon afterwards, resulting in another sound defeat. At the same time, the Danish offensive in the west saw a halt, with their main force moving back and forth from Lubeck to Berlin, without ever being able to besiege the latter successfully.
Another offensive by Bogusław followed, soon after regrouping in the fortress in Nakło (in southern Pomerellen province), this time into the heart of Poland proper - Warszawa. There, the army was defeated, despite the numerical superiority of the Pomeranian troops. The disorganized Poemranians fled into Ziemia Sieradzka (Syradia), while the victorious Polish were, seemingly again for no reason, called to the east of the country. This made it possible for Bogusław to return to Warszawa, assaulting the city in a matter of two days. At the same time, a smaller Pomeranian reinforcement from Szczecin was sent, with orders to help Bogusław, by attacking Warszawa from the eastern bank of the river. Once still in Mazowsze, they defeated a similarly-sized army under Zamoyski. After taking Warszawa, Bogusław ordered the combined forces toward Sieradz, besieging the city. Reports of a considerably large army from Meissen assaulting Poznań reached the Pomeranian commander, who decided to attack Sieradz, hoping to take the city within two days (in which he succeeded), and moved north, to take command of the forces in Wielkopolska and take hold of the other cities in the province himself.
The manoeuvre was a success, to the anger of the duke of Meissen, who wrote letters to Ernest Ludwik of Pomerania, complaining about Bogusław 'stealing the cities of Wielkopolska from the hands of his troops like a common thief'. The king responded to this: 'Gniezno, Poznań and other cities have belonged to Pomerania for more than a half of a century before the war had started; therefore, Pomerania considers these lands as her own territory, carved out from her illegally by the treacherous Hungarian king on the throne of Poland. Because of this, all claims of the duke of Meissen are absolutely groundless, and will not be taken into account'. Ernest knew well that Meissen was one of the smallest and weakest countries in the Holy Roman Empire which, if left without the assistance of Pomerania and Saxony, would lose her independence very soon. Due to that, he Ernest didn't treat the complaint from the duke too seriously.
Meanwhile, everything became more complicated on the western front: the long-forgotten revolt in Rostock had become a German quasi-independence movement. The burghers of the city declared themselves independent from the Pomeranian authority, hoping to be aided by the Danes - the aid, however, didn't come. Ernest Ludwik couldn't send any forces to make short work of the revolters, with the campaign in Poland becoming increasingly demanding and problematic. He saw the troubles and unrest the prolonged war was causing throughout the entire country, but on the other hand, Bogusław's army was quite successful in its efforts, and the king dreamed of even receiving some territory from Poland as a compensation for the war effort.
The Polish used the confusion, caused by Mecklemburg's independence, to march on Warszawa and retake their capital, and then to move into Wielkopolska. There, however, their new king (Zygmunt III) was reached with the news of a new Pomeranian assault on Warszawa. This news was, seemingly, too much for the Swede on the Polish throne: he sent an envoy to Ernest, promising to end the hostilities between their countries and hand Wielkopolska and Kujawy to Pomerania. The king of Pomerania was more than happy to accept such a deal - it was much mor than he had actually expected. Now, what remained, was the question of the Danish incursion and the independence movement in Rostock...