Greetings from Mexico.
The "anonymous romance" was arranged by Spanish classical guitarist Narciso Yepes (1927-1997) from an old Spanish song for the film score of the 1952 movie Jeux Interdit, (Forbidden Games) directed by René Clement. While his widow defends his authorship of the piece, the film credits him for "musical adaptation and interpretation" and the popular sheet music at (
http://guitarra.artelinkado.com/guitarr ... ersion.jpg)
of the film score for Jeux Interdit lists the author as "anoymous."
A different version of the piece was used in an older film score, the one for the 1941 film "Blood and Sand," based on the book by Vicente Blasco Ibañez, directed by Ruben Mamoulian. This was a story about bullfighting, filmed in Mexico. The guitarist who interpreted the piece at that time was Vicente Gomez (1911-2001). The movie starred Tyrone Power.
Gómez edited his own version of the Romance en 1940, some 11-13 años before Narciso Yepes-, with the following title: "Romance de Amor, Canción Tema, Música de Vicente Gómez". You can find documentation on the different versions of the romance at the following link.
http://guitarra.artelinkado.com/guitarr ... php#mnota6.
It's clear that at least 13 years before Narciso Yepes arranged his version, the Romance was well-known as far away as Mexico as a piece in the guitar repertoire.
Francisco Herrera dates the first printed edition of the Romance at the end of 1930 and no later than January 1931.
This was the version of Daniel Fortea, a fine Spanish Classical Guitarist 1882-1953. "Romance Anónimo, de Daniel Fortea" This version is available for free at Eythorsson.com.
Another version gives authorship to Miguel Llobet (1878-1938). Curiously the copyright is dated 1968, so it´s clear that it is a posthumous transcription of an earlier recorded work by that composer.
Still others give earlier authorship. See the above link in Spanish for more info on the Romance.