Rottenbuch Abbey (German: Kloster Rottenbuch) in Rottenbuch 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. Rottenbuch was a center of papal loyalty during the Investiture Controversy. Under the patronage of Emperor Louis the Bavarian in the 14th century, together with its location on the pilgrimage route to Italy, Rottenbuch became the most influential house of Canons Regular in Germany.