  Fermat's Last Theorem is proved by using the philosophical and mathematical
knowledge of 1637 when the French mathematician Pierre de Fermat claimed to
have a truly marvelous proof of his conjecture. Our approach consists of
setting three variables of Fermat's equation as integers and then evaluating
whether the remaining variable can be an integer as well. Pythagorean triples
play a fundamental role in claiming that at least an irrational number is
needed to satisfy Fermat's equation. As a result, we confirm that Fermat's Last
Theorem is valid.
