James Corum wrote that it was a myth that the "Luftwaffe" had a doctrine of terror bombing, in which civilians were attacked to break the will or aid the collapse of an enemy, by the "Luftwaffe" in "Blitzkrieg" operations. After the bombing of Guernica in 1937 and the Rotterdam Blitz in 1940, it was commonly assumed that terror bombing was a part of "Luftwaffe" doctrine. During the interwar period the "Luftwaffe" leadership rejected the concept of terror bombing in favour of battlefield support and interdiction operations.