From the works Matthias Weckmann wrote for the Collegium Musicum, eleven autograph sonatas are preserved in the Lüneburg Council Library. While two of the sonatas call for a conventional trio of two violins and bass (in the tenth sonata a viola da gamba and in the eighth a dulcian), the remaining, more extravagant pieces are written for a heterogeneous quartet of cornettino (treble zinc), violin, trombone (in two sonatas alternatively viola da braccio and viola da gamba), and dulcian or bass shawm. In the pieces for the Hamburg Collegium Musicum, Weckmann pushed all of the instruments, but especially the trombone and cornettino, to their absolute limits. An important characteristic of the sonatas are the strong contrasts. Typical features are: abrupt changes of tempi, meter, and tessitura (sometimes accompanied by echo effects), close and wide harmonies, and alternating polyphonic and homophonic passages in which three instruments occasionally play parallel chords as in a faux bourdon. Notwithstanding these commonalities, each sonata is an individual piece and not forced into any prefabricated mould.