Mielczewski is first mentioned in 1638 as a court musician in Warsaw. He was probably already active there as the court composer and was possibly active in the chapel of Lowicz before coming to Warsaw. The director of music for the king's brother from 1648 until his death, Mielczewski was recognized as a leader among his contemporaries. Compositionally Mielczewski was a prolific composer who wrote with a concertato framework. This form dominated his music. Diverse sacred concertatos were composed employing only a few voices to poly-vocal settings. Mielczewski's compositions demonstrated a sensitivity to the texts of his works as well as an awareness of the expressive possibilities available through music. Madrigals by Mielczewski do not survive but his accompanied masses were scored for a large number of voices. A few instrumental canzonas demonstrated his acumen for clear, concise and precise formal structures as well as an ability to compose using variations. He would often imitate Polish religious songs in his sacred music with minimal modifications. The rhythmic dance, specifically the Polish structure of the mazurka, was first found in the music of Mielczewski. ~ Keith Johnson, Rovi