Johann Dismas Zelenka (1679-1745) was a Baroque composer active in Dresden. He is also known as Jan Dismas Zelenka. He was highly regarded by Johann Sebastian Bach, and wrote a number of orchestral and vocal pieces which are virtuosic and demanding. He was an assistant to Johann David Heinichen, and unsuccessfully tried to gain the post of Kapellmeister after Heinichen's death in 1729. The post went to Johann Adolf Hasse.