Looking into the history of science, I've been struck by how continuous scientific progress seems. Although there are many examples of great intellectual breakthroughs, most of them build heavily on existing ideas which were floating around immediately beforehand - and quite a few were discovered independently at roughly the same time (see https://en.m.wikipedia.org/wiki/List_of_multiple_discoveries).
So the question is: which scientific advances were most ahead of their time, in the sense that if they hadn't been made by their particular discoverer, they wouldn't have been found for a long time afterwards? (Ideally taking into account the overall rate of scientific progress: speeding things up by a decade in the 20th century seems about as impressive a feat as speeding things up by half a century in ancient Greece).
I was a bit confused here. Do you mean the rediscovery provides evidence that the idea was ahead of its time, especially when the rediscovery was much later, because we have an actual counterfactual?