Johann Dubez Allemagne 1828 - 1891. His compositions make extensive use of the 10-string guitar, and it is nearly fruitless to attempt these pieces with less than an 8-string instrument. It also requires 22-24 frets on some pieces, clearly for the Staufer-style guitar. Most of the works are extremely difficult, with fast note flourishes, and clearly written for virtuoso players. In the later 19th century, as the romantic period flourished, instrumental virtuosity and sentiment were prevalent and sometimes overdone.
The Fantaisie Hongrois stands out as probably the best work, and Robert Trent has included this in concert programs. It borrows from the Mertz piece of the same title but is a new composition. While challenging, it is not impossible to play.
Michael Sieberichs-Nau has researched Dubez, and points out that these works are elaborate, only for professionals (like Liszt). Apparently, only 2 works by Dubez were published, and probably due to the technical requirements, other pieces were probably sold as hand-copied manuscripts individually by the composer, a practice which is well-documented during this time period and done by Mertz (Hide extended text) ... (Read all) Source : Wikipedia