text: According to the music historian Daniel Heartz, there has been considerable controversy concerning Gluck's native language. Gluck's protégé in Vienna, the Italian-born Antonio Salieri, wrote in his memoirs (translated into German by Ignaz von Mosel), that "Gluck, whose native tongue was Czech, expressed himself in German only with effort, and still more so in French and Italian." Salieri also mentions that Gluck mixed several languages when speaking: German, Italian and French, like Salieri himself. Gluck's first biographer, , wrote that Gluck grew up in a German-speaking area, and that Gluck learned to speak Czech, but did not need it in Prague and in his later life. Heartz writes: "More devious manoeuvres have been attempted by Gluck's German biographers of this [the 20th] century, while the French ones have, without exception, taken Salieri at his word. His German biographer Max Arend objected that not a single letter written in Czech can be found, to which Jacques-Gabriel Prod'homme countered that "no letters written by Liszt in Hungarian were known either, but does this make him a German?" Hans Joachim Moser wanted a lyric work in Czech as proof. In fact, the music theorist Laurent Garcin, writing in 1770 (published 1772) before Gluck arrived in Paris, included Gluck in a list of several composers of Czech opéras-comiques (although such a work by Gluck has yet to be documented). A presentation by Irene Brandenburg classifying Gluck as a Bohemian composer was considered controversial by her German colleagues.