The Withdrawing Room

I'm watching a documentary on Highclere Castle, which is where Downton Abbey is filmed.  The narrator refers to the Drawing Room and the Withdrawing Room.  Modern life is so far from conceiving of a Withdrawing Room.

Of course, one needed to be an earl to have a Withdrawing Room.  If you were a servant, you were squeezed three into a Tiny Attic Room.