Comment by jhbadger

If anything, art history defines "modern" later than the real historical meaning ("modern art" starts in the 1860s after the invention of photography). In history modernity starts in the 1500s - in Western culture history is divided into ancient (dawn of civilization to fall of Rome), medieval (fall of Rome to the Renaissance) and modern (Renaissance to now). You'd need a fall of civilization or something to justify a new era.