The original concept of The Lion King does not belong to Disney. It was based off the series "Kimba the White Lion." If you don't believe me, look it up, or just watch the show. There is even a site dedicated to proof that Disney stole it. (As I cannot find the site, feel free to browse this cracked! article: http://www.cracked.com/article_17299_6-famous-characters-you-didnt-know-were-shameless-rip-offs.html )
I will also list some facts here anyway: Aside from the obvious name similarities, the original adds for The Lion King had Simba's fur color as, yes, white. The voice actor for Simba stated that he came in honestly expecting a remake of that series. The main villain of the lion king? Simba's uncle. One of the main villains of Kimba the White Lion?
Kimba's aunt. How does Simba have a big, life-changing revelation? Seeing his daddy in cloud form in the sky. Kimba has an almost identical moment, but over a different issue. And just to assure you that Kimba is the original, not only was it made first, but Disney tried, prior to making the Lion King, to get the rights to the actual show for YEARS, but the owner refused...
So what did they do? Screwed around with the plot just enough to claim innocence. They still wanted to keep Simba's fur white, but one of the developers was quoted saying "C'mon, guys, not even OUR lawyers are THAT good." (Cracked will also point out to you that Simba's life is -also- based on Hamlet, so even the changes that -were- made to make it "original" were not original.)
But you know... I'm surprised if this shocks anyone. Most of Disney's "classics" are not original stories. They're fairy tales that have been around for years. Disney just dolled them up in pretty morals and made them kid-friendly. (And if you don't realize that fairy tales were not originally for kids due to their once incredibly violent, bloody, dark, and emotionally scarring nature... well, research the original versions at your own--childhood's--risk. Rape and dismemberment are among the reasons.)