In the early years of the century, Wagnerian chromatic harmony was extended by opera composers such as Richard Strauss ("Salome", 1905; "Elektra", 1906–1908; "Der Rosenkavalier", 1910; "Ariadne auf Naxos", 1912; "Die Frau ohne Schatten", 1917), Claude Debussy ("Pelléas et Mélisande", 1902), Giacomo Puccini ("Madama Butterfly", 1904; "La fanciulla del West", 1910; "Il trittico", 1918), Ferruccio Busoni ("Doktor Faust", 1916, posthumously completed by his student Philipp Jarnach), Béla Bartók ("Bluebeard's Castle", 1911–17), Leos Janáček ("Jenůfa", 1904; "Osud", 1907; "Kát´a Kabanová", 1919-1921) and Hans Pfitzner ("Palestrina", 1917).