Although it is usually presented as an original work by Spanish guitar composer Francisco Tárrega, it is actually a transcription of the second section of Robert Schumann's Phantasietanz, Op.
Since Tárrega was working on the piece shortly before he died, it is possible he intended to transcribe all of it but that assumption can not be confirmed.
The part Tárrega did transcribe shows several differences in the original, all fairly typical of what can be expected in a guitar transcription of a piano work.
The main difference between Schumann's piano work and Tárrega's transcription is tempo indication.
Without access to the original manuscript it is impossible to tell whether this re-interpretation was made by Tárrega or by the publisher.