Originally Posted by
bat39
Yeah, the Batman mythos, for the most part, have stayed pretty consistent. In fact, its more or less possible to view Batman's history from 1939 to the present-day as virtually one unbroken line (with a few cosmetic changes here and there) - which is in fact what Grant Morrison did. The fact that is relatively easy to reconcile all the different iterations of Batman is IMO one of the reasons why the Batman fanbase is also relatively more united than the Superman fanbase (where you have constant debates about different versions of Superman).
Over time, the major changes/additions to Batman continuity have been:
-A significant expansion of the Wayne family legacy and their significance to Gotham history. Originally, Thomas Wayne was just a wealthy doctor who happened to be the victim of an unfortunate crime alongside his wife. But over time, this has shifted to the point where the Wayne family were basically Gotham royalty, Thomas and Martha Wayne were philantrophists on a mission to save Gotham, and the Wayne industrial empire is worth billions. The idea that Bruce's activities as Batman are in some way a continuation of the Wayne family legacy (an idea that Snyder pretty explicity leaned into in Zero Year) stems from that. On a related point, originally Wayne Manor was just a house Bruce purchased well after becoming Batman, but now its not only Bruce's childhood home, but also the ancestral home of the Wayne family.
-Alfred's importance in Bruce's life is a major retcon that has resonated through all contemporary adaptations of the Batman mythos. Originally, Alfred was the son of the Wayne family's former butler, who, per his father's dying wish, entered Bruce's employ long after Bruce and Dick were well-established as Batman and Robin. Alfred, while he was a valuable ally to Bruce, was never as close to him as Dick was. But now, Alfred has not only been with the Wayne's since Bruce was a child (if not before his birth), but he practically raised Bruce and is basically a surrogate father to him. He's also Bruce's very first ally, and his closest confidant.
-Gotham City has fundamentally changed in many ways. Originally, it was a standard fictional city, a faux-NYC with a fairly 'normal' crime rate. At some point in the 70's, and certainly after Miller's Year One it was re-characterized as this cesspool of crime and corruption that was virtually beyond hope. This has, to a large extent, changed the nature of Batman's mission as well. Originally, his parent's death was simply a crime, and he wanted to spend his life "warring against all criminals". While that is still technically true, in the current context, the Wayne murders have become a symptom of the rot that infests Gotham, and so Batman's mission (or rather obsession) is about warring against the darkness of Gotham - or at least keeping it at bay. Batman's not just a crime-fighter anymore, he's someone trying to save his city.
These are the really big ones. There are tons of smaller, superficial changes. For instance, was Joe Chill a hitman or a mugger (and was the murderer Joe Chill at all?) Where did Bruce get trained to become Batman? At what age did Dick Grayson become Robin? How did Jim Gordon get allied to Batman? But the three I've mentioned above are the fundamental changes that have really reshaped the mythos over the last 30-40 years.