I don't know if this was a concept introduced Post-Zero Hour or not, but after rereading the Long Halloween, it occurred to me that DC by the 90s had rectonned a great deal of Batman's rogues gallery such as the Mad Hatter, the Riddler, Poison Ivy, Calendar Man, and even Man Bat to have made their debut before Dick Grayson became Robin.
If you even have a passing familiarity of Batman's publishing history, like me, your going think this is rather odd. While Robin first appeared in 1940, the Mad Hatter first appeared in 1948, Two Face in 1942, Man Bat in 1970, Penguin in 1941, Poison Ivy in 1966, Riddler in 1948, Scarcrow in 1941. The only member of Batman's main rogues gallery you could say existed before Robin is Hugo Strange.
In my mind, the continuity of Post Crisis Batman should in large carry over from Earths One and Two with a few minor exceptions such as Jason Todd's revised origin. Am I the only one who is bugged by this?