My grandfather on my father's side, staff, infantry lieutenant colonel (also sniper) Gottfried von Hammerstein und Hartmann in the German Army (1936-1945), he served:

As a military liaison, observer and translator in Spain, late 1937.
As personal secretary and adjutant to field marshal Fedor von Bock, 1938.
As infantry-platoon commander, Poland 1939 and France 1940.
As translator, adjutant and liaison to field marshal Friedrich Paulus in his journey to North Africa and vist to field marshal Erwin Rommel in 1941.
As infantry-battallion commander, Russia 1941-1944.
As infantry-armoured liaison in Italy, late 1944.
As regimental commander, Berlin 1945.

My grandmother from my father's side, She was a Hauptgruppenführerin in the Luftwaffehelferinnenschaft (1944-1945), I think. I am messed up with the information.

Also, many others in my father's side served in the German military, specially Army and Navy.

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"War is less costly than servitude, the choice is always between Verdun and Dachau." - Jean Dutourd, French veteran of both world wars

"A mon fils: depuis que tes yeux sont fermes les miens n’ont cessé de pleurir." - Mère française, Verdun