The Grossmünster is one of three main churches in Zurich (the other two are the Cathedral of Notre Dame and St. Peter's). The church is located near the banks of the Limatt River and was opened around 1100 and around 1220. The church across the river from the Cathedral of Notre Dame played a major role in the 16th century Swiss Reformation, where the University of Zurich Theological Seminary and the Museum of the Reformation were established, and the painted glass inside the church is the masterpiece of Swiss modern art master Giacometti.