In most iterations of the team, they are led by their founder Charles "Professor X" Xavier, a powerful telepath who runs a school for mutant children out of his mansion in Westchester, New York, which secretly is also the headquarters of the X-Men. Their stories have frequently involved Magneto, a powerful mutant with control over magnetic fields, who is depicted as an old friend of and foil to Xavier, variously acting as an adversary or as an ally.
