During the
Invasion of Poland, Suwalska Cavalry Brigade, under General
Zygmunt Podhorski, belonged to
Independent Operational Group Narew, and its task was to protect the approaches to Grodno and cover northern flank of the Narew Group. It concentrated all its subunits by September 2, 1939, and manned its positions along the border with
East Prussia. On the same day, the
Wehrmacht unsuccessfully attacked
Bakałarzewo. In the night of September 3/4, two squadrons of 3rd Regiment of Mazovian Chevau-légers carried out a successful raid over several villages of East Prussia. Soon afterwards, Polish headquarters ordered the Brigade to move southwards, to forests between
Putusk and
Ostrów Mazowiecka. Polish planners wanted to attack German forces which marched along western bank of the
Narew. In the night of September 4/5, the Brigade began its march from the area of Suwałki to
Zambrów, via
Knyszyn and
Tykocin. On September 7, it reached the village of
Jabłoń Kościelna, and on September 9–10, Colonel
Kazimierz Plisowski temporarily commanded the Brigade. At the same time, it was engaged in heavy fighting with German
Panzer Division Kempf. On September 9 in the morning, the Brigade was ordered to attack German positions in the villages of
Piski and Ksiezopole. By afternoon, both villages were captured, with numerous prisoners of war. In the evening the Brigade retreated to forests around
Koskowo, but without 2nd Grochów Uhlans, which was ordered to protect the wing of Polish 18th Infantry Division, and on September 10 was engaged in heavy fighting near
Rutki. On 10 Sept., the brigade, under the command of Gen.
Zygmunt Podhorski, was pinned down by the
10th Panzer Division (Wehrmacht) south of the
Biebrza River. On September 11 the Brigade retreated south of Zambrów, and on the next day, it merged with remnants of
Podlaska Cavalry Brigade, creating Operational Group of General Podhorski. In the night of September 13/14 near
Olszewo, the Brigade was involved in heavy fighting, which caused its partial destruction. In revenge for the losses suffered in the battle, German troops of the
206th Infantry Division perpetrated a massacre of 30 Polish POWs and 23 civilians in Olszewo on 14 September 1939 (see
Nazi crimes against the Polish nation). Survivors fled to
Białowieża Forest, where by September 20, Plis Cavalry Brigade (named after Colonel
Kazimierz Plisowski) was created. ==See also==