Wonder Woman was first created by William Moulton Marston in 1942, halfway through the Second World War and was initially depicted fighting Axis military forces as well as an assortment of colourful supervillains, although over time her stories came to place greater emphasis on characters, deities, and monsters from Greek mythology.
In the DC Universe timeline that came to be established, Superman was meant to be the first of the 'modern-day' superheroes, with Batman and Wonder Woman following. and all having helped fight in World War II. Eventually, the Justice Society of America and Justice League Of America were divided by continuities and DC's main superheroes had their origins moved forwards in time, Wonder Woman's mother Hippolyta now having fought in World War II.
This kind of thing kept getting amended until the New 52 came along, and reduced Wonder Woman's experience in the DC Universe to five years, as was Superman, Green Lantern, Flash and more – only Batman got an additional five years of history. But the Wonder Woman movie took a more classical view.
It had been established in Batman Vs Superman that Wonder Woman had been around a while. And in her movie, we saw it was one of a hundred years ago, fighting against the German allies in World War I.
When the DC Timeline was leaked by DC Comics at New York Comic Con, it established as Wonder Woman having been around before World War II and preceding Superman by decades as the first superhero of the DC Universe, and emerging at the same time Krypton explodes. And, however that is going to be handled, earlier this week Bleeding Cool learnt that it will be established that she fought in World War One – just like the movie. And that the motto for 5G and the new DC Timeline as a whole is that "everything happened"…
Apart from shooting Maxwell Lord in the head. For now.