First appearance of John Henry Irons as Steel in The Adventures of Superman #500. This marks the debut of the character and his introduction into the DC Universe, during the "Reign of the Supermen" storyline following Superman's death.

Superman's first appearance in Action Comics #1. This event marks the beginning of the Golden Age of Comic Books and establishes Superman as the archetypal superhero. This event is the base of most DC superheroes including John Henry Irons, which is inspired by Superman