Wikipedia: Carl von Clausewitz

Carl Phillip Gottleib von Clausewitz (1780-1831).

Prussian military thinker; attained the rank of Major-General in the Prussian Military. Famous for writing the military strategy book Vom Kriege ([On War]?).

Married Countess [[Marie von Brühl]].

Sources:

http://www.clausewitz.com/CWZHOME/CWZBASE.htm