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. In 1941, two higher grades of the Knight's Cross were instituted.
As the war advanced, some 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 established. The Oak Leaves, commonly known as such, were based on the enactment of June 3, 1940. In 1941, two additional grades of the Knight's Cross were introduced.