Did Fermat Prove His Last Theorem?

Although he claimed to have a general proof of his conjecture, Fermat left no details of his proof, and no proof by him has ever been found. His claim was discovered some 30 years later, after his death. This claim, which came to be known as Fermat's Last Theorem, stood unsolved for the next three and a half centuries.

Why didn't Fermat prove his last theorem?

Not enough of his writings have survived to guess what that method was, and the proof he gave for n=4 doesn't generalize in any obvious way to other exponents. It is simply not possible that Fermat discovered a proof which is equivalent to Wiles' proof.

Did Fermat really prove his last theorem?

"Yes, mathematicians are satisfied that Fermat's Last Theorem has been proved. Andrew Wiles's proof of the 'semistable modularity conjecture'--the key part of his proof--has been carefully checked and even simplified.