Editing Extended chord (section)

===20th century===
[[File:Fifteenth chord from Listz on B.png|thumb|A diatonic fifteenth chord on B opens [[Franz Liszt]]'s ''[[List of compositions by Franz Liszt (S.1–S.350)|Ossa arida]]'' (1879), in, "a striking anticipation of twentieth-century harmonic experimentation".<ref>{{cite book|editor-last=Arnold|editor-first=Ben|date=2002|title=The Liszt Companion|page=361|publisher=Greenwood|isbn=9780313306891}}</ref> {{audio|Fifteenth chord from Listz on B.mid|Play}}]]

In the 20th century, especially in jazz and popular music, ninth chords were used as elaborations of simpler chords, particularly as substitutes for the tonic triad at the end of a piece.<ref name="Grove"/> The "piling up" of thirds above the tonic to make seventh, ninth, eleventh, or even thirteenth chords "is one of the most important characteristics of [[jazz harmony]]".<ref name="Grove"/> [[Vítězslav Novák]]'s student [[Jaroslav Novotný]] (1886–1918) used a fifteenth chord in the fourth song of his 1909 song cycle ''Eternal Marriage''.<ref>{{cite book|last1=Schweiger|first1=Dominik|last2=Urbanek|first2=Nikolaus|date=2009|title=webern_21|page=45|publisher=Böhlau Verlag Wien|isbn=9783205771654}}</ref>