period piece
US /ˈpɪr.i.əd ˌpiːs/
UK /ˈpɪr.i.əd ˌpiːs/

1.
a work of art, literature, or music that reflects the style or characteristics of a particular historical era
:
•
The film is a beautiful period piece set in the 1920s.
•
Her novel is a meticulously researched period piece.