The name of this internationally renowned group means bow and gut strings. In its almost decade-long existence, its membership has continually changed from two to eight string performers with several constant players: Vera Beths, Jürgen Kussmaul, and Anner Bylsma. This continuous regrouping allows the musicians to present a wide repetoire of pieces and also fits their desire to enjoy performing with a variety of musician friends, rather than attempting to maintain a fixed form as a string quartet or quintet. The group emphasizes the authentic presentation of works of the eighteenth, nineteenth, and twentieth centuries, and prefers to play on gut strings in order to realize the older timbres in performance.