Caesar one night camped near the town of Varennes-sur-Allier, where there had previously been a bridge before Vercingetorix had destroyed it. That night, he divided his force into two parts, one part being two thirds of the force, the other being one third of the force. He ordered the larger force to march in six corps as if it were really the full army of six legions. He then ordered it to continue its march south. Vercingetorix, duped, took the bait and followed this part of the force.