Short form for Johann Kaspar Mertz Mertz is now considered one of the finest guitarist-composers of the nineteenth century, his music having less affinity with the previous generation (Sor, Giuliani, Aguado) than with the piano music of Schumann and Mendelssohn. He is also often grouped with Giulio Regondi and Napoléon Coste, the other leading guitarist-composers of his time. He learnt to play both guitar and flute to a very high standard, and had much success as a performer in Vienna, where he moved in 1840.