Rottenbuch is a municipality in the Weilheim-Schongau district, in Bavaria, Germany. Rottenbuch Abbey was founded as an Augustinian monastery in 1073 on land granted by Duke Welf I of Bavaria. The Abbey church was constructed between 1085 and 1125 in the Romanesque style. The design of a crossing transept and free-standing tower is unusual for a Bavarian church. In the 18th century the medieval interior of the church was redecorated in the ornate High Baroque style by painter Matthäus Günther and stuccoist Josef Schmuzer. With the secularization of the Bavarian monasteries under Montgelas in 1803 the monastic buildings were pulled down and the noteworthy library sent to a paper mill; the Abbey church became a parish church, which it remains to this day.