High Quality Content by WIKIPEDIA articles! The German operation for the invasion of Denmark and Norway in April, 1940 was code-named Weserübung, or "Weser Exercise." Opposing the invasion were the partially mobilized Norwegian military, and an allied expeditionary force composed of British, French, and Free Polish formations. The following list formed the order of battle for this campaign. On 1 March 1940, the German 21st Army Corps was renamed Group XXI and placed in charge of the invasion of Norway. The group was allotted two Mountain and five Infantry divisions for this task. It was led by the commanding officer of the XXI Korps, General der Infantrie Nikolaus von Falkenhorst. His Chief of Staff was Colonel Erich Buschenhagen.