I can't imagine ABDL as we currently see it today going back any farther than the 1960s at the earliest. I'm sure before then, there were probably some who had ABDL tendencies, wanted to regress, and would've been ABDLs if they were around today. I know people have brought up the ideas of ABDLs going back 100 years ago. Well Psychology has only been thought of as a science since the 1870s, so it's been around for less than 150 years. I'm guessing that if you had the desire to be little or regress way back before the industrial revolution, you either kept those desires deep in the closet, or you'd probably be written off as weak, lazy, not pulling your weight around helping contribute to the survival of the species, or possessed by the devil. You would NOT have wanted to be an ABDL way back then.