Former imperial powers can struggle to let go. The Portuguese, some five hundred years past their peak, even have a word for it. From The Rest is History’s four-episode romp through Portuguese history (start at the beginning):

The famous Saudade of the Portuguese is a vague and constant desire for something that does not and probably cannot exist. For something other than the present, a turning towards the past or towards the future. Not an active discontent or poignant sadness but an indolent dreaming wistfulness.

The show draws the quote from the book In Portugal by A.F.G Bell

Saudade has a Wikipedia entry with an arresting painting by the same name (below).

Saudade (1899) by Almeida Junior