The German composer Wolfgang Amadeus Mozart (1756-1791) was not only a musical genius, but was also one of the pre-eminent geniuses of the Western world. He defined in his music a system of musical thought and an entire state of mind that were unlike any previously experienced. A true child prodigy, he began composing at age 5 and rapidly developed his unmistakable style; by 18 he was composing works capable of altering the mind-states of entire civilizations.