Where did the phrase 'top drawer' originate?

Scotland. One of the bedrooms of Glamis Castle, in Scotland, contains a chest of seven drawers that was designed for holding and organizing the royal occupant's clothing. Clothing was placed in one of the chest's drawers depending on the day of the week it was for. Thus, starting with Monday's clothes, these were stored in the drawer closest to the floor. Next, Tuesday's clothes were in the next drawer up and so on for the clothing for each day of the rest of the week, with the top drawer designated for Sunday's clothing. Since the garb for Sunday was traditionally the finest of the week, the expression "top drawer" came to be associated with "the finest".