Composed in 1727 and lost for over 100 years, Bach's St. Matthew Passion is widely regarded as one of the greatest masterpieces of Baroque sacred music. The first performance of the piece was given at the Leipzig Thomaskirche, on Good Friday of 1727, but Bach substantially revised his greatest, most complex liturgical work in 1736, and the Tahoe Symphony presentations are based on that version. The St Matthew Passion, in this form, was his last major composition for the Leipzig congregations. The St. Matthew Passion was written for two separate Choirs, accompanied by two small Orchestras. In most Arias, only one Orchestra provides accompaniment. The Choirs are sometime separated, but more often sing in unison or antiphony - moving the story forward and also providing commentary on the events. At different times, the Choruses appear as an unruly mob, or quiet witnesses, or actual participants in the story.