The Battle of Joniec was fought on 14 October 1655 between the armies of Poland-Lithuania and Sweden amid the Deluge.
In October 1655, the Swedes launched counteroffensives into Poland, hoping to regain the initiative after the loss of Warsaw to the Poles. On the same day as King Carl Gustaf's defeat at the Battle of Garbów outside Lublin, Fabian von Wersen's Swedish army attacked Alexander Casimir Wolowicz's Polish army northwest of Warsaw. Jerzy Wisniewski and his mercenary band arrived just in time to come to Wolowicz's aid. In the ensuing battle, a cavalry clash saw the Poles overwhelm the Swedish cuirassiers and dragoons before meeting the Swedish infantry in battle. The superiority of the Swedish pikemen inflicted significant losses on the Poles, but the Polish army was eventually able to overwhelm and destroy the Swedish force. Fabian von Wersen was captured, sealing his army's annihilation.