The 'Battle of Kałuszyn' was fought between small German and Polish forces in the area of the town of Kałuszyn near Mińsk Mazowiecki as part of the German 'Weiss' (i) invasion of Poland (11/12 September 1939).
After the 'Battle of the Borders', the Polish forces of Generał brygady Wincenty Kowalski’s Operational Group 'Wyszków' began a steady withdrawal, characterised by delaying actions, in the area to the north-east of Warsaw. Following the 'Battle of Pułtusk' and the 'Battle of Różan', the Polish 1st Legions Division reinforced by the units of the Operational Group 'Wyszków' arrived in the area of Mińsk Mazowiecki, where they were overrun by Generalleutnant Max Bock’s 11th Division, a formation of General Walter Petzel’s I Corps in General Georg von Küchler’s 3rd Army of Generaloberst Fedor von Bock’s Heeresgruppe 'Nord', which managed to take the town and surround the Polish forces.
The Polish aim was now to retake the town and break through the German encirclement before Panzer reinforcements arrived and the German capability became stronger. After a short preparation, the battle began overnight with a Polish assault on the villages surrounding the town. The Polish forces managed to break through the positions of the 44th Infanterieregiment, which was disorganised after its rapid advance and had underestimated the strength of the Polish forces still in the area.
At one point a Polish commander ordered the 4th Squadron of the 11th Uhlans Regiment to advance towards the town itself. The order was mistakenly understood as an order for a cavalry charge and the squadron, numbering 85 men and commanded by Porucznik Andrzej Żyliński, charged toward the German positions with drawn sabres, breaking through to the town despite suffering the loss of 33 men killed. The Polish infantry followed into the breach in the German defences and by the early morning the town had been retaken and the German division forced into a retreat.
The losses on each side had been significant. The commanding officer of 44th Infanterieregiment, Major Krawutschke, committed suicide. In the course of the heavy fighting, the town was almost completely destroyed. Most of the substantial Jewish population of the town was later deported by Germans to the Warsaw ghetto or Treblinka extermination camp.