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 beyond the comic books. Superman, Inc. merged with DC Comics in October 1946. After DC Comics merged with Warner Communications in 1967, licensing for Superman was handled by the Licensing Corporation of America. The Licensing Letter (an American market research firm) estimated that Superman licensed merchandise made $722 million in sales globally in 2017. 44.7% of this revenue came from the North American market. For comparison, in the same year, Spider-Man merchandise made $1.4 billion and Star Wars merchandise made $2.4 billion globally. The earliest paraphernalia appeared in 1939: a button proclaiming membership in the Supermen of America club. The