DC Comics is no stranger to alternate universes. Its history is nothing if not a slow gradual process of bringing its various superheroes into a single narrative, resulting in multiple realities and periodic Crises to straighten things out. All this without taking its formal Elseworlds line into account, nor the various TV and movie adaptations of their deep well of characters. The cinematic DC Universe is just the latest incarnation of a very old tradition.
Source：https://www.cbr.com/the-batman-robert-pattison-earth1-earth2-inspiration/
