The Battle of Brest was fought on 18 June 1655 between the armies of Poland-Lithuania and Sweden amid "the Deluge."
After inflicting several defeats on the Swedes in Galicia and Lesser Poland, Poland's armies marched north to recapture the Swedish-occupied fortress of Berestye (Brest), which lay just 128 miles east of the Polish capital of Warsaw. The Swedish general Magnus Gabriel de la Gardie marched to Brest's relief, but the Poles temporarily abandoned the siege of Berestye to confront De la Gardie's army just beyond the city walls. In the ensuing battle, the Poles utilized their superiority of cavalry and numbers to overwhelm the Swedes, whose unarmored infantrymen were easily cut down by Jerzy Wisniewski's fast-moving mercenary cavalry. Swedish pikemen inflicted serious losses on the Polish cavalry, but the Swedish army was ultimately annihilated. De la Gardie evaded capture, but the loss of his army was a major blow to the faltering Swedish war effort.