Béla Viktor János Bartók (; ; March 25, 1881 – September 26, 1945) was a Hungarian composer and pianist. He is considered one of the most important composers of the 20th century; he and Liszt are regarded as Hungary's greatest composers . Through his collection and analytical study of folk music, he was one of the founders of comparative musicology, which later became ethnomusicology. On 1 January 2016 his work entered the public domain in the European Union.