These courses he taught helped popularize the notion that there was a scapegoat responsible for the outbreak of war and Germany's defeat. Hitler's own bitterness over the collapse of the war effort also began to shape his ideology. Like other German nationalists, he believed the "Dolchstoßlegende" (stab-in-the-back myth) which claimed that the German Army, "undefeated in the field", had been "stabbed in the back" on the home front by civilian leaders and Marxists, later dubbed the "November criminals". "International Jewry" was described as a scourge composed of communists relentlessly destroying Germany. Such scapegoating was essential to Hitler's political career and it seems that he genuinely believed that Jews were responsible for Germany's post-war troubles.