Monday's Riddle!

Here's this week's riddle! Good luck everyone! ~F

An Emperor lost in time, was angered when his robes he could not find.
Others would also stare, if you looked down and I was not there.
I can be made of most anything. 
It all depends on my threads and string.
Whatever the colors swirling in your head... 
Perhaps purple or blue? Maybe black or red...
Fashion and style can change my look, depending on the latest book.
So try me on, but take care, without me, you'll be bare. 


What am I?

Check back later if you need to get a clue...