The Battle of Warsaw (Schlacht von Warschau; Bitwa pod Warszawą; Tredagarsslaget vid Warszawa) was a battle which took place near Warsaw on July 18 1656 – July 20 1656, between the armies of the Polish-Lithuanian Commonwealth on the one hand and of Sweden and Brandenburg on the other. It was a major battle in the war between Poland and Sweden in the period 1655-1660, also known as The Deluge (part of the Northern Wars).
In the battle, a smaller Swedish-Brandenburg force gained victory over a Polish-Lithuanian force superior in numbers, though in the long term the victory achieved little. Polish-Lithuanian losses were insignificant, and even though Swedish forces were able to reoccupy Warsaw, they were forced to abandon it soon afterward.
The Polish-Lithuanian forces, commanded by King John II Casimir of Poland, comprised about 24,000 regulars (including only 950 Winged Hussars - 8 banners), 2,000 Tatars and 10,000 of the noble levy (pospolite ruszenie), altogether some 36,000 men of which only about 4,000 were infantry and the remainder cavalry & dragoons, with 18 artillery pieces. The allied armies of Sweden and Brandenburg, commanded by King Charles X of Sweden and Elector Frederick William of Brandenburg, were only 19,000 strong, and after landing at Danzig, marched south towards Warsaw. It fielded 12,500 cavalry & dragoons, 6,500 infantry (15 brigades) and 47 artillery pieces. Second in command of Brandenburg's forces was Otto Christoph von Sparr.
John II Casimir ferried his army across the Vistula River and met the approaching Swedish-Brandenburg force on its right bank, about five kilometers to the north of the suburb of Praga. Charles X had initially hoped to destroy the Lithuanian and Tatar forces before they joined up with the remainder of the Commonwealth army, but this plan failed. Many officers of Sweden and Brandenburg considered the Polish-Lithuanian forces to be overwhelming in numbers and instead advocated a retreat.
On the first day, the Swedes and Germans mounted a conventional, frontal assault which was resisted and repulsed. The space between the Białołęka Forest to the east and the Vistula River on the west made the line of battle very narrow and prevented the Swedish and German infantry from forming an effective firing line with their muskets and pikes. The Polish-Lithuanian forces had also thrown up earthwork fortifications in front of their positions, creating a very difficult defensive position to assault.
On the second day, Frederick William led a personal reconnaissance mission and noticed that a hillock against the forest, known as the "Colline", was on high enough ground to see over the Białołęka Forest and was also a prime position to put his guns. He had it assaulted and occupied by Brandenburg's infantry and dragoons and soon positioned his cannon on it, holding off against repeated Polish charges against the hillock.
With the Germans having shifted attention to the Colline hillock, the highly mobile Swedish cavalry began a daring maneuver. Wheeling around the Białołęka Forest unseen and to the Polish-Lithuanian right flank, they consolidated a new position which made the Poles' battle lines untenable. The sudden appearance of the Swedish army on their flank caused them to rush uncoordinated attacks that petered out by nightfall, although mounted Tatar forces continued to harass the allied forces.
During the night, John II Casimir realized that victory was unattainable and decided to evacuate the baggage train and his infantry across the Vistula River, while the cavalry was to prolong the fighting in order to cover the retreat and then withdraw south along the river.
The third day was when the Commonwealth forces were finally defeated. The planned retreat was poorly executed and on most parts a failure. During the night, horses and infantry started to cause a traffic jam on the bridge across to the Warsaw-side of the river.
At sunrise, around 4 a.m., the allied forces got into battle position while the Polish forces, led by John II Casimir himself, readied themselves. Around 8 a.m. the allied forces started their attack. Field Marshal von Sparr began an hour-long bombardment and followed with a pike charge against the now demoralized and unorganized Commonwealth forces. Frederick William led a cavalry charge to the right and broke deep into the rear of the Polish lines, causing a general disintegration of their forces.
A dispute regarding the tactics between Swedish and Brandenburg officers gave several Polish regiments the opportunity to withdraw towards the bridge. At this time, the bottleneck on the bridge’s eastern side caused a panic and many Commonwealth soldiers fell into the water. Amongst those who came close to drowning were Stanisław "Rewera" Potocki and Jan Zamoyski. The bridge collapsed but was soon repaired while dragoons held off the Swedish-Brandenburg attacks. When the artillery and infantry was across the bridge, John II Casimir ordered it to be burnt down in order to halt the pursuing Brandenburg cavalry.
Left on the eastern bank were the majority of the Polish cavalry. Numbering about ten thousand, the force started to maneuver south through a narrow corridor. The allied officers were surprised by this bold move and did not mount a flank attack that would have cut off the Polish forces and caused a catastrophe for them. Instead, the battle ended with Swedish cavalry cutting down and capturing the remaining scattered forces, amongst many were nobility from Belz.
The Germans and Swedes held a victory parade through the streets of Warsaw, but they were unable to hold it and were soon forced to abandon the city. The Polish king's defeat led him to concede sovereignty over the Duchy of Prussia to Brandenburg in return for an alliance in the Treaty of Wehlau the following year.