Wolfgang Mozart was born on January 27, 1756 in Salzburg. When Mozart was only four years old, he could play little pieces on the harpsichord. Also, for ten years, Wolfgangs father was his manager from the time he was six to age sixteen.
Some of the other famous composers like Beethoven had to work their way up from the bottom up. Mozart was already famous because his family was already famous. So he an advantage, which I think helped him become so successful.