Charlie: Well, I can proof Fermat's last theorem.
This is a reference to a medieval mathematician Pierre de Fermat. In 1637 he wrote in his book that he has proved mathematically a certain statement in number theory, but he didn't write the proof itself. It took 357 years for the rest of the world to proof Fermat's statement. In 1995 British mathematician Andrew Wiles published his proof of that theorem, thus ending one of the oldest riddles in the world of mathematics. Simon Singh published in 1998 his book Fermat's Enigma telling the whole story of this riddle from its conception till the solution.