World war 1.
Yes, he served in the German army in WW1 with the rank of corporal.
Hitler was in WW1 as an enlist man in the German army. He was the rank of a corporal.
(German Navy) in 1922.
no
Yes, in the Imperial German Army during the First World War fighting on the western front in France.
no
yes
I don't think he did.
No
He served as an officer with Military Intelligence.
"Mussolini wanted to prove to his Axis partner that he was capable of leading Italy to a similar military successes" is the evidence that Mussolini was ever jealous of Hitler.