yes
Well over 600.
He was able to compose his first symphony at about the age of 5, from there on he composed till December 5th his death day.
yes.
No. 1 in E flat major, at the age of 8! Magg811- Mozart started getting interested in piano at age 3, and became a master at the violin and piano at age 4 and created his first symphony at age 5....
The Surprise Symphony