FYI: It turns out that there are Old Testament scholars who believe the book of Isaiah was written by multiple authors because it was impossible for one man to have written all of it. They were referring to his prophecies, especially those mentioning King Cyrus by name over a hundred years before his time. Because they did come to pass just as Isaiah had said, scholars thought they must have been written by at least two different people from different times.
However, if God can do something as impossible as show one man the future, I'm sure he can do something as easy as give someone great talent so that that man's works would have a such a profound effect on the world that they'd still be around centuries after his lifetime--and Shakespeare's writings have definitely influenced the world, often for the better (even when "for the better" simply means that they've given people a chance to challenge their brains or to connect to/gain an understanding of other people or to ponder deeply about problems and situations that have influenced the human race and even directed its history for all the millenia we've been around on this earth).
Even if Shakespeare was simply a genius in his field, he wasn't the only one the world has ever seen; watch this to learn about this young man's road to fame and glory (you don't have to watch the entire thing, just the first 3 minutes are fine):
Homeless Boy Wows Judges
By the way, I love how the hosts of Korea's Got Talent build up the performers; it's such a relief to see that nowadays!