Sláva Vorlová (born Johnová, 1894–1973), who also became known under her pseudonym Mira Kord, is certainly one of the most important Czech women composers of the 20th century. She ran a musical salon in Prague with her husband in the 1930s and was active as a composer until the 1970s. Like Agnes Tyrrell (1846–1883) or Vítězslava Kaprálová (1915–1940), she shows that the composing of women was by no means concentrated on typical forms such as song or pieces for piano, but also broke new ground. Her Concerto for Bass Clarinet and Strings op. 50, for example, is considered the first concerto for this instrument in music history. She had also turned to avant-garde as well as serial music at the pulse of the times, at the same time operas, choral works and unusual instrumentations up to the dulcimer.
It was not until relatively late that she began composing professionally. She came from a musical household and had received singing, piano and composition lessons at a young age. After her marriage to the entrepreneur Rudolf Vorel (1891–1945), however, it was first necessary to expand the family business. It was not until the 1930s that she was able to continue her studies first privately and after the second world war in master classes at the Prague Conservatory in the class of Jaroslav Řídký (1897–1956). A String quartet, Op. 1 "Bezkydy" and song collections Op. 2 and Op. 4 are among Vorlová’s earliest works, which do not yet foreshadow the horror that was to change her life shortly before the end of the war. She had to witness the execution of her husband by the Nazis, a trauma that left its mark on her and was processed in her music. Her work during the war and shortly thereafter is characterized primarily by patriotic themes, such as the choral cycle Bílá oblaka op. 8 (White Clouds, 1942–1943), which uses the national anthem, or the Symphony JM for Orchestra, Op. 18 (1947–1948), dedicated to the death of Jan Masaryk.