Placide Cappeau was the author of "O Holy Night" which was set to music by what French composer and music critic
Placide Cappeau: Placide Cappeau (October 25, 1808 – August 8, 1877) was a French poet and the author of the well-known poem, "Minuit, chrétiens" ("O Holy Night") (1847), which was set to music by Adolphe Adam. Adolphe Adam: Adolphe Charles Adam (] ; 24 July 1803 – 3 May 1856) was a French composer and music critic.
Adolphe Adam