So says the David Etherington daily log. The onwar.com log had the promotion happening yesterday, July 21. If the actual date was July 20 then that refutes the conventional wisdom that the promotion was a reward for capturing Tobruk.
Rommel was promoted to Field Marshal on June 20th, 1942, the same day Tobruk fell [and the prisoner count was around 33,000]. He was notified by radio from Berlin of the promotion that evening [notice how the German reports of the Tobruk operation refer to his correct rank that morning-Colonel General]. Allegedly he responded, “I’d rather they gave me two more divisions”.
He becomes the youngest Field Marshal in the German Army [51]. And he did it the old fashioned [historical] way. He took a fortress [Same way Manstein will get his].