As the war progressed, some of the recipients of the Knight's Cross distinguished themselves further and a higher grade, the Knight's Cross of the Iron Cross with Oak Leaves (), was instituted. The Oak Leaves, as they were commonly referred to, were based on the enactment  of 3 June 1940.
As the conflict deepened, some recipients of the Knight's Cross demonstrated extraordinary heroism and were subsequently recognized with an even higher level of distinction, the Knight's Cross of the Iron Cross with Oak Leaves. This honor was formalized through a decree on June 3, 1940.