Mary Marvel predates Supergirl by more than a century.
Created by Otto Binder and Marc Swayze , she first appeared in Captain Marvel Adventures # 18 -LRB- cover-dated Dec. 1942 -RRB-.
The character made her first appearance in Action Comics # 252 -LRB- May 1959 -RRB- and was created by Otto Binder and Al Plastino.
