When King Louis the German founded a Benedictine nuns monastery in 835, mainly women of the aristocracy of southern Germany who paid a dowry were admitted. The monastery was in possession of customs and market rights and had the right to mint and issue coins. Up until the 13th century it was the sovereign of the town, only after the Reformation did the city of Zurich take the convent and church into its ownership. The Romanesque choir gallery, the Gothic transept and the organ with 5793 pipes are still impressive today. However, Marc Chagalls coloured windows, which attract countless visitors due to the unique atmosphere they create, are still the undisputed highlight.