Carl von Clausewitz (1780 - 1831) was a Prussian general and military theorist who stressed the "moral" (in modern terms, psychological) and political aspects of war. His most notable work, Vom Kriege (On War), was unfinished at his death. Clausewitz was a realist and, while in some respects a romantic, also drew heavily on the rationalist ideas of the European Enlightenment. He stressed the dialectical interaction of diverse factors, noting how unexpected developments unfolding under the "fog of war" (i.e., in the face of incomplete, dubious, and often completely erroneous information and high levels of fear, doubt, and excitement) call for rapid decisions by alert commanders. He saw history as a vital check on erudite abstractions that did not accord with experience. He argued that war could not be quantified or reduced to map-work, geometry, and graphs. Clausewitz had many aphorisms, of which the most famous is "War is the continuation of politics by other means."