The battle of Prostki took place during the Second Northern War and was a decisive victory of Polish-Lithuanian forces numbering 10,000 men (mostly regular cavalry) supported by 2,000 Tatars and led by hetman Wincenty Gosiewski over a Swedish-Brandenburg army of 6,500 regulars (nearly half of them infantry) reinforced by 800 Lithuanian-Polish cavalry of prince Boguslav Radziwill and led by prince Georg Friedrich von Waldeck. The battle was portrayed in the Polish movie “Potop” from 1974.
Wincenty Korwin Gosiewski
After the retreat of combined Swedish-Brandenburg armies from Warsaw in 1656, the Polish commanded decided to spare no expense in attacking the territories of Ducal (Polish) Prussia, which despite being a Polish fief had allied itself with the Swedish King. One of the objectives during this campaign was to completely destroy Prussian territory to force Frederick Wilhelm’s mindset in co-operating with the Swedish invader. A victorious battle against a combined Swedish-Brandenburg-Prussian army conducted under the command of Field Hetman of Lithuania, ‘Wincenty Gosiewski’, during the Prussian campaign in the time of the Swedish-Muscovite Deluge on Poland in 1654-1660. The Polish-Lithuanian army was composed of Lithuanian units, Crown units (Poles), pospolite ruszenie (general levy) and tartars. The whole army was counted at about 12-13,000 men, most of it cavalry including about 2,000 tartars. Enemy forces under the Swedish General Waldeck were counted at much lower; 2,500 cavalry, 1,000 Prussian infantry (general levy) and 6 artillery pieces, as well as about 800 cavalry under the command of the traitor, Boguslaw Radziwill. Other Swedish commanders in the area heard of the approach of the Polish-Lithuanian army, (namely General Walenrodt and Colonel Josiass Waldeck), who would supply an additional 2,000+ infantry. Total forces were then were around 5,500 men, the bulk of which was Brandenburg infantry.
Gosikewski arrived at Prostek on the right bank of the river Elk and decided to immediately attack the Brandenburg forces, after which he would completely destroy any more advancing formations. He also sent the tartars for a preliminary confrontation with the forces of Wallenrod.
The Lithuanian units used the old trick of ‘feinting retreat’ (which worked so well at Kircholm, and by the tartars so many hundreds of years ago), against the Prussian infantry, which fell for this maneuver and moved across the river to the right side of the bank. Gosiewski’s army surrounded the Prussian infantry, attacked, and their formations broke. Much of the infantry was forced back into the river, either drowning or being killed however a few units together with some artillery pieces managed to escape back to the other side of the bank. The Lithuanians and Tartars immediately charged after them capturing their base of operations very quickly. After this, together with some Tartars then moved to attack the 800 cavalry under Radzwill, which they managed to attack from behind and flanks. Most of his cavalry was killed, only a few successfully retreated the rest were captured, including Prince Radziwill himself. The battle ended at 2pm with a successful attack on the formations of General Waldeck which were almost completely defeated. The rest of the army moved to attack the retreating infantry formations of Wallenrodt which was exhausted by a long march when retreating being continuously attacked by Tartar units.
Total Swedish-Brandenburg losses in this battle amounted to about 5,000 men (over 75% of the entire army), whilst Polish-Lithuanian army losses amounted to no more than around 200-250 dead. The defeat was so great that the population of Ducal Prussia demanded that Frederick Wilhelm sign a treaty with the Poles immediately, however it never came to that. Whilst this was a great victory, proving that the Polish-Lithuanian army was again a competent force, though victories continued to be on/off affairs, it would be an uphill battle to ride the enemy from the country which had entrenched itself so completely.