The music was written by Richard Rodgers, with words by Lorenz Hart, for the 1927 musical A Connecticut Yankee. The lyric is notable, as indicated by the title, for its mix of archaic English and modern slang as the story takes place in both contemporary times and in King Arthur's court.
Recordings
An early recorded version featured The Broadway Nitelites conducted by Ben Selvin with vocals by Franklyn Baur (Columbia 1928).
In the MGMTechnicolor biopic about Rodgers and Hart called Words and Music (1948), June Allyson sings and dances to Thou Swell with twin "knights" in an appropriately medieval setting.
The music of the song is featured in the film All About Eve (1950). It is played on the piano at the party when Margo tells her friends to "fasten their seat belts."