[Question] Which scientific discovery was most ahead of its time?

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).