In September 1939 he took part in the invasion of Poland as commander of a detachment .
Cramer enlisted in the Prussian Army on 10 August 1914 and served in World War I ; he was retained in the Reichsheer .
In September 1939 Cramer took part in the invasion of Poland as commander of a detachment .
Cramer enlisted in the Prussian Army on 10 August 1914 and served in World War I ; he was retained in the Reichsheer .