Throughout history composers have written music for women to sing together to exploit the unique harmonics and resonances of the female voice. The most widely known early music for upper voice is probably that of Hildegard von Bingen from the 12th century. Since then, most composers have written for female choirs; there are well known works by Palestrina, Victoria, Purcell, Brahms, Holst, Schubert, Mozart and Poulenc amongst the more than 14,000 pieces of music widely available today. And the rich blend of sonority achieved by three, six or nine part harmonies continues to be exploited by modern composers such as Gjeilo, Todd, Rutter and Jenkins, all writing specifically for the female voice.