Spanish Romance, Romanza – Anonymous. This comes from my Classical Guitar Repertoire Lessons Grade 5 book. Five pieces at the grade 5 level with dedicated lessons preparing you for each piece. I also have this piece as a single selection with an addition video and free notation edition.
Spanish Romance (Romanza) – This is an iconic work and may the most popular and well recognized works for classical guitar by the general public. The composer is anonymous. Also known as “Romance Anónimo” (Anonymous Romance), “Estudio en Mi de Rubira” (Study in E by Rubira), “Romance de España”, “Romanza” and “Romance d’Amour” and more titles. Includes fingering.
More info on the piece via its Wiki: “Its origins and authorship are in question. It is suspected of originally being a solo instrumental guitar work, from the 19th century. It has variously been attributed to Antonio Rubira, David del Castillo, Francisco Tárrega, Fernando Sor, Daniel Fortea, Miguel Llobet, Antonio Cano, Vicente Gómez, and Narciso Yepes. The Anónimo (anonymous) part of its name has been incorporated over the years due to this uncertainty. The question of authorship has probably been propagated by three main reasons: the lack of claim by its true author, the desire to avoid paying copyright fees, and the desire of publishing companies to claim the lucrative copyright of this world-famous piece. The style of the piece is that of the Parlour music of the late 19th century in Spain or South America, having a closed three-part form: the first in the minor key and the second being in the major key, with the third being a restatement of the first.”
The piece is certainly not by Sor, that is just way off, but Tarrega would not be a huge stretch. Though, if it was by any legit composers I would imagine the piece has been altered overtime to simplify it and make it more pleasing for mainstream consumption.