period piece

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