Alternative versions of Superman establish a new continuity for DC, affecting not only Superman, but all of the DC Comics characters. The versions of Superman from this time period are traditionally divided into three main periods. The first version of Superman began being published by DC Comics in 1938 appearing in "Action Comics" #1. To explain discrepancies in the aging of Superman across several decades, his earliest stories were retroactively portrayed as having taken place on an alternative world called Earth-Two. These stories take place from 1938 until the late 1950s, although the exact dividing line is unclear and some stories happened identically to
Superman character and cast as well as the Justice League of America and the Super Friends (of which Superman is usually a member and most of the time, the leader). Team-ups with fellow comics icon Batman are a fan-favorite, inspiring many stories over the years. When paired, they are often referred to as the "World's Finest" in a nod to the "World's Finest Comics" series that mostly featured team-up stories between Superman and Batman during its 45-year history. In 2003, DC Comics began to publish a new series featuring the two characters titled "Superman/Batman". Minor supporting characters over the years have included Superman's technological