中世紀

Madison Primo

Wow I wasn't ready for this one 

Nora

I really don't know about it.

Sara Severini

Giusto dubbio

Amy fung yee Leung

sorry I don't know about it 

Mary ALice Blanchard

I believe it will always be that time frame, for the middle ages. I see what you're asking but I think each era has their own definition. Like the roaring twenties, etc.  As time continues, I don't think that will change each era or time frame.