 The Oak Leaves, as they were commonly referred to, were based on the second Knight's Cross related enactment of 3 June 1940.In 1941, two higher grades of the Knight's Cross were instituted.The enactment of 28 September 1941 introduced the Knight's Cross of the Iron Cross with Oak Leaves and Swords () and the Knight's Cross of the Iron Cross with Oak Leaves, Swords and Diamonds ().