The Mighty Thor making his debut in Jouney to Mystery issue 83 of august 1962. Being the son of a god Thor was sent to earth by his father oden to make him learn about humanity but he was stripped of his powers and his god status.
Apon arriving on earth as his alter ego Donald Blake he witnessed the arrival of an alien scouting party, Blake then flees into a cave and discovers Thors disguised hammer Mlolnir by striking it against a rock Blake transformes into the thunder god Thor.