 Later, in twelve-tone music, serialism, and other 20th century compositional idioms, composers considered it a neutral interval.In some analyses of the works of 20th century composers, the tritone plays an important structural role; perhaps the most cited is the axis system, proposed by Ernő Lendvai, in his analysis of the use of tonality in the music of Béla Bartók.Tritone relations are also important in the music of George Crumb and Benjamin Britten, whose "War Requiem" features a tritone between C and F♯ as a recurring motif.