Hirsau Abbey

Hirsau Abbey, formerly known as Hirschau Abbey, was once one of the most important Benedictine abbeys of Germany. It is located in the Hirsau borough of Calw on the northern slopes of the Black Forest mountain range, in the present-day state of Baden-Württemberg. In the 11th and 12th century, the monastery was a centre of the Cluniac Reforms, implemented as "Hirsau Reforms" in the German lands by William of Hirsau. The complex was devastated during the War of the Palatine Succession in 1692 and not rebuilt. The ruins served as a quarry for a period of time.

A Christian chapel at Hirsau dedicated to Saint Nazarius had already been erected in the late 8th century. The monastery itself was founded in about 830 by the Rhenish Franconian count Erlafried of Calw at the instigation of his son, Bishop Notting of Vercelli, who gave it the relics of Saint Aurelius of Riditio, an Armenian bishop who had died about 475, brought from Milan among other treasures.