Beginning on the 25th there were clashes at Palencia and Villamuriel de Cerrato as Souham sought to turn the Allied north flank. Wellington then adopted an unorthodox defensive position, prompting Souham to pause for two days. The stalemate was broken on 29 October when a party of naked French soldiers swam the Duero River at Tordesillas with their weapons on a raft. Upon reaching the far bank, they took up their guns and routed the Brunswick defenders of a key bridge. With an intact bridge in French hands, Wellington was forced to continue his retreat toward Portugal.