Leoš Janáček (Czech: [ˈlɛoʃ ˈjanaːtʃɛk] ; 3 July 1854 – 12 August 1928) was a Czech composer, music theorist, folklorist, publicist and teacher. He was inspired by Moravian and other Slavic music, including Eastern European folk music, to create an original, modern musical style.
Born in Hukvaldy, Janáček demonstrated musical talent at an early age and was educated in Brno, Prague, Leipzig, and Vienna. He then returned to live in Brno, where he married his pupil Zdenka Schulzová and devoted himself mainly to folkloristic research. His earlier musical output was influenced by contemporaries such as Antonín Dvořák, but around the turn of the century he began to incorporate his earlier studies of national folk music, as well as his transcriptions of "speech melodies" of spoken language, to create a modern, highly original synthesis. The death of his daughter Olga in 1903 had a profound effect on his musical output; these notable transformations were first evident in the opera Jenůfa (often called the "Moravian national opera"), which premiered in 1904 in Brno.