Yes, he often borrowed source material, but it’s what he did with it that is so amazing. The story of a Danish prince wasn’t all that interesting, and who would have otherwise guesses that a write could make something so sublime of it. It’s the language, the wit, the psychology, the metaphysics, that make Shakespeare great. To worry about the source material is missing the point entirely. I can guarantee you, no one is reading Saxo or Belleforest today, because they think it is fsantastic.
That may be true, but his authorsip is in doubt, and not to knock your screen name, but The Great Gatsby was the most painful expierence of my high school years.
Authors in those days generally did not do all original work. If they did it would have then been disregarded as of no value.
Art was in reworking already known themes and incidents with one’s own insights and techniques.