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
Origin of Superman time in "Superman" #61. "Action Comics" #158 retold the origin again, this time acknowledging the adventures of Superboy. After Mort Weisinger took over as editor of the Superboy comics in 1953, the mythology of Superman began growing, starting with the introduction of Superboy's pet Krypto the Superdog, the first survivor of Krypton in comics other than Kal-El himself. When Weisinger became editor of the entire Superman line in 1958, the Superman mythology began expanding even more rapidly. Producing over a hundred Superman stories a year, Weisinger aimed to introduce a new element to the character's mythology every six months. By