Mozart's workload

The Holland writer Hendrik Willem van Loon say in his book The story the art that he thought Mozart's death is caused by his working hard.
His workload is so heavy, that is equivalent to
make dozens of people work hard to death in five or six years
Mozart is really a genius. He can create in such a hurry time, it's in such a hurry that he said some notes dropped down off the table but the products are still so great.

Hendrik Willem van Loon (1882-1944)'s book list:
  1. The Fall of the Dutch Republic, 1913,
  2. The Rise of the Dutch Kingdom, 1915.
  3. The Short History of Discovery, 1917,
  4. Ancient Man, 1920
  5. The Story of Mankind, 1921, ( Awarded by The annual Newbery Medal in 1922, which had been created by Unitarian bookseller and editor Frederic Melcher to honor outstanding American children's books.)