Earth that existed within its own fictional "universe" and could communicate with the Earth of the current, revised versions of those characters. Alternative-reality Earths had been used in DC stories before, but were usually not referred to after that particular story. Most of these alternative Earths were usually so vastly different that no one would confuse that Earth and its history with the so-called real Earth. That would change when the existence of another reliable Earth was established in a story titled "Flash of Two Worlds" in which Barry Allen, the modern Flash later referred to as the Flash of Earth-One (the setting of the Silver Age stories) first travels to another Earth, accidentally vibrating at just the right speed to appear on Earth-Two, where he meets Jay Garrick, his Earth-Two counterpart. He claims Gardner Fox's dreams were tuned into Earth-Two, explaining their depiction as a fictional world in earlier Barry Allen stories. Expanding the concept: revisiting 1940s superheroes Superman was introduced in the 1930s and was the archetype for the modern superhero, and so is depicted in stories set on Earth-Two as the first major reliable costumed superhero on that world, discounting earlier part-time heroes and "mystery men" such as Doctor Occult. Most of the following costumed mystery men history is based on the Earth-Two Superman's initial appearance, where these previously independent operating heroes begin to reliably interact. In order to distinguish him from the later primary version of the character, this Superman was called "Kal-L", using the spelling of Superman's Kryptonian name in his early appearances. He was specifically introduced as an Earth-Two character in Justice League of America #73 (1969). Most superheroes from the Golden Age later followed this trend of operating publicly, while wearing distinctive costuming and interacting in a largely shared universe. The primary characters of Superman and Batman still largely worked independent of team environments. In the 1970s, as the now annual team up between the Justice League of America and the Justice Society of America had proven popular, DC published the then present day adventures of the Justice Society in the revived All-Star Comics with issue #58, resuming the numbering from the series' original run. The story continued in Adventure Comics #461–466, which featured the death of the Earth-Two Batman in issue #462. Mr and Mrs Superman, a feature in Superman Family (1974–1982), featured stories of the adventures of married Superman and Lois