The concept of the Sturmgeschutz III started well before the war when the German army announced the need for a self-propelled 75mm gun to be used for infantry support. By 1938, several '0-Serie' prototype vehicles were produced on earlier style Panzer IIIB chassis by Daimler-Benz. The manufacture of the first 30 production vehicles (StuG III Ausf. A) that went into combat in the invasion of France were made at the Alkett factory in Berlin. As the war progressed, the StuG III was continuously improved with variants A through E, and then given a longer, more powerful gun starting with the...