52 BC: Caesar conquered Gaul "If you must break the law, do it to seize power: in all other cases observe it." In the Battle of Alesia (September, 52 BC), Caesar built a fortification around the city to besiege it. However, Caesar's army was surrounded by the rest of Gaul, and Vercingetorix had summoned his Gallic allies to attack the besieging Romans, so Caesar built another outer fortification a