on 28 may 1940, hitler had ordered the creation of a new panzer group under the leadership of heinz guderian. on 1 june 1940, guderian was assigned to the command of "panzergruppe guderian", taking most of the staff from xix army corps with him. the panzer group was assigned command over two army corps: xli corps, still under command of reinhardt, and xxxix corps under rudolf schmidt. panzer group guderian became part of wilhelm list's 12th army.