>>22342367it's not really a condition in its own right, as much as it is a label for the behavioral and cognitive traits which arise from idiosyncratic neural architectures—differences in the brain's structure and functioning, as compared to a normal person's
the causes for the differences seem to be myriad, and their precise nature is idiosyncratic (and can be advantageous, deleterious, or a mixture of both, dependent on context), though there's often overlap: social awkwardness and inability to distinguish between multiple overlapping conversations are pretty typical AFAIK
I think we can find accounts of historical persons who sound very much like autists or 'spergs, and there's no reason for there not being people with unusual neural topologies at any given point in history, so I'd say with almost complete certainty that it's something which has always been around
perhaps the more pertinent question is "is prevalence of autism increasing, or is there simply more recognition these days?"