13th century. Not just the art, but for the content. Truly ahead of its time.
And the Space Age is really the tail end of the Steam Age. Human history doesn't have any sharp divisors, aside from total genocides or the even rare natural disasters on the scale of Pompeii's demise.
The admittedly artificial definition of the start of the Renaissance, however, does help frame an explosive growth of useful new tools in art (and other endeavors), like perspective, oil paints, and so on.
Obviously, there is no sharp line. That is too trivial to mention. But the distinction is made, because it captures something about the characteristic spirit of an age.
In the received black legends of whig history, the Renaissance is typically presented as some kind of enlightened rift with and rebellion against the supposedly dark and evil Middle Ages, but in some sense, it is more accurate to view it as a culmination of the Middle Ages or something continuous with it.
You will find great rifts later on with the rise of modernism.
People flatter themselves.