Musical instruments have been used since the earliest times for a variety of purposes, ranging from the entertainment of concert audiences to the accompaniment of dances, rituals, work, and medicine. The use of instruments for religious ceremonies has continued down to the present day, though at various times they have been suspect because of their secular associations. The sound produced by an instrument can be affected by many factors, including the material from which the instrument is made, its size and shape, and the way that it is played.