The Musikkollegium Winterthur was founded in 1629 and has been a professional symphony orchestra since 1875. With around 50 musicians, it is now one of the leading symphony orchestras in Switzerland. A good 50 concert programs per season in the Stadthaus Winterthur, as well as numerous chamber music events and opera and ballet performances in collaboration with the Theater Winterthur and the Zurich Opera House demonstrate the orchestra's broad spectrum. Classical and romantic music are the mainstays of the orchestra's extensive repertoire, which ranges from baroque to contemporary music. Famous soloists and conductors such as Kit Armstrong, Isabelle Faust, Sol Gabetta, Reinhard Goebel, Teo Gheorghiu, Heinz Holliger, Andreas Ottensamer, Michael Sanderling and Sir András Schiff are regular guests of the Musikkollegium Winterthur.