La Marseillaise as theme material (leitmotiv) in Casablanca (Curtiz 1942)
The Marseillaise is codified as the French Republic Anthem, but it does not refer particularly to France through musical style or orchestration.
Chopin’s 2d Sonata Funeral March is codified as the conventional funeral march, although other funeral marches have been composed throughout history.
Chopin, Frédéric [Composer] – Chopin: Piano Sonata No.2 in B flat minor, Op.35 – 3. Marche funèbre (Lento)
Academy New Schola Cantorum – Marche Funèbre
Robot Chicken 6×01: the conventionally codified Funeral March versus non-codified music
Brahms’ Lullaby has become as well the conventional lullaby (Relaxing Piano Music – Brahms Lullaby).
The conventional lullaby (Brahms) in How I met your Mother 6×18
The conventional lullaby in a Japanese context: Okuribito
As opposed to real lullabies that people may sing to the children, if they are not conventionally recognized they may fail to be understood by the audience, for instance traditional Georgian Lullabies