During the Thirty Years' War, Sweden managed to conquer approximately half of the member states of the Holy Roman Empire. The fortunes of war would shift back and forth several times. After its defeat in the Battle of Nördlingen (1634), confidence in Sweden among the Swedish-controlled German states was damaged, and several of the provinces refused further Swedish military support, leaving Sweden with only a couple of northern German provinces. After France intervened on the same side as Sweden, fortunes shifted again. As the war continued, the civilian and military death toll grew, and when it was over, it had led to severe depopulation in the German states. Although exact population estimates do not exist, historians estimate that the population of the Holy Roman Empire fell by one-third as a result of the war.